ORIGINAL RESEARCH * NOUVEAUTES EN RECHERCHE

Economic impact of HIV infection and coronary heart disease in immigrants to Canada Hanna Zowall, MA; Louis Coupal, BSc; Rod D. Fraser, PhD; Norbert Gilmore, PhD, MD; Antal Deutsch, PhD; Steven A. Grover, MD, MPA, FRCPC Objective: To compare the direct health care costs of illnesses associated with the human immunodeficiency virus (HIV) and of coronary heart disease (CHD) in immigrants to Canada. Design: Comparative cost analysis. Participants: All people who immigrated to Canada in 1988. The numbers with HIV infection and CHD were estimated from country-specific HIV seroprevalence data and national CHD mortality statistics and data from the Framingham study. Health care costs, projected over the 10 years after immigration, were calculated on the basis of data, from the Hospital Medical Records Institute and provincial fee schedules. Results: Of the 161 929 immigrants in 1988, 484 were estimated to be HIV positive. The total cost of treatment of HIV-related illnesses from 1989 to 1998 (discounted at 3%) would be $18.5 million: $17.1 million would be spent on the outpatient and inpatient care of the HIV-positive immigrants, $1.0 million on care of the subsequently infected sexual partners and $0.4 million on care of the HIV-positive children born to seropositive immigrant women. In comparison, CHD would develop in 2558 immigrants during the same 10-year period. The total CHD costs would be $21.6 million: $8.4 million would be spent on treating myocardial infarction, $3.2 million on coronary artery bypass grafting, $1.6 million on pacemaker insertion and $8.4 million on treating other CHD events. Conclusions: The economic impact of HIV infection in immigrants to Canada is similar to that of CHD. This comparison identifies an important shortcoming in current immigration policy: economic considerations can be arbitrarily applied to certain diseases, thereby discriminating against specific groups of immigrants.

Objectif: Comparer les couits directs de soins de sante attribuables aux maladies associees au virus de l'immunodeficience humaine (VIH) et a la cardiopathie isch& mique (CI) chez les immigrants au Canada. Conception: Analyse comparative des couits. Participants: Toutes les personnes qui ont immigre au Canada en 1988. Le nombre de sujets a infection au VIH et de sujets a CI ont e evalues d'apres les donnees de seroprevalence du VIH specifiques aux pays vises et la statistique nationale de Ms. Zowall, Mr. Coupal and Dr. Grover are with the Centre for the Analysis of Cost-Effective Care and the Division of Clinical Epidemiology, Montreal General Hospital, Montreal, Que. Dr. Grover is also with the Division of General Internal Medicine, Montreal General Hospital, and the departments of Medicine and of Epidemiology and Biostatistics, McGill University, Montreal, Que. Dr. Fraser is with the Department of Economics, Queen's University, Kingston, Ont. Dr. Gilmore is with the McGill Centre for Medicine, Ethics and Law and the McGill AIDS Centre, McGill University. Dr. Deutsch is with the Department of Economics, McGill University.

This study was presented in part at the 7th International Conference on AIDS, held in Florence, Italy, June 17-18, 1991. Reprint requests to: Dr. Steven A. Grover, Division of Clinical Epidemiology, Montreal General Hospital, 1650 Cedar Ave., Montreal, PQ H3G IA4 OCTOBER 15, 1992

CAN MED ASSOC J 1992; 147 (8)

1163

mortalite due a la CI, de meme que des donnees de l'etude Framingham. Les couts de soins de sante, projetes sur 10 ans apres l'immigration, ont ete calcules d'apres les donnees de l'Hospital Medical Records Institute et les baremes de frais des provinces. Resultats: Des 161 929 immigrants de 1988, on estimait que 484 etaient seropositifs. Le cofit total de traitement des maladies liees au VIH de 1989 a 1998 (actualise a 3 %) serait de 18,5 millions de dollars: 17,1 millions de dollars pour les soins des immigrants seropositifs en consultations externes et hospitalises, 1 million de dollars pour les soins des partenaires sexuels infectes subsequemment et 0,4 million de dollars pour les soins des enfants seropositifs nes de femmes immigrantes seropositives. Par comparaison, la CI apparaitrait chez 2 558 immigrants pendant ces memes 10 annees. Le couit total de traitement des CI serait de 21,6 millions de dollars: 8,4 millions de dollars pour le traitement des infarctus du myocarde, 3,2 millions de dollars pour les greffes d'arteres coronariennes de derivation, 1,6 million de dollars pour l'implantation de pacemakers et 8,4 millions de dollars pour le traitement d'autres manifestations de CI. Conclusions: L'effet economique des infections au VIH chez les immigrants au Canada est analogue a celui de la cardiopathie ischemique. La comparaison degage une importante lacune dans la politique actuelle d'immigration: des considerations economiques peuvent etre appliquees arbitrairement a certaines maladies, entrainant une discrimination a l'endroit de groupes specifiques d'immigrants.

S creening potential immigrants for human immunodeficiency virus (HIV) infection has become the subject of increasing public debate.' The rationale includes the expectation that exclusion of those who are seropositive may limit HIV transmission and reduce the demands on the health care system. The latter consideration is particularly relevant in Canada, where immigrants would become the consumers of publicly financed health care services. However, to determine whether a specific minority of immigrants represents a financial burden on the health care system requires more than simply estimating the health costs associated with a specific disease.4 The economic burden of the disease in question must be compared with that of other prevalent diseases (for which immigrants may or may not be currently screened) to develop a policy that is rational, practical and fair. To provide a basis for the development of a rational immigration policy relating to HIV infection we have estimated and compared the cumulative direct medical costs attributable to HIV infection and coronary heart disease (CHD) that would be expected to accrue over the 10 years following the arrival of immigrants in Canada in 1988.

Methods Estimation of HIV seroprevalence and duration of HI V infection Since potential immigrants to Canada are not screened for HIV antibodies we estimated the HIV seroprevalence rate among the 161 929 immigrants who entered Canada in 1988.5 It was considered to be the same as the national rate in their countries of last permanent residence. National seroprevalence 1164

CAN MED ASSOC J 1992; 147 (8)

data for 80 countries was obtained from published reports (data available from the authors upon request). We calculated low and high rates with 95% confidence limits around each point estimate using the binomial method or the exact method when appropriate. When country-specific data were unavailable continent-specific seroprevalence data were obtained from the World Health Organization (WHO) (Michael Merson, director, WHO Global AIDS Program: press conference, 6th International Conference on AIDS, San Francisco, June 20, 1990) and from a sample of potential immigrants to the United States.6 Only immigrants without clinically detectable acquired immunodeficiency syndrome (AIDS) were included in this model, since all potential immigrants must undergo a medical examination and only those without AIDS would be eligible to immigrate. All HIV-positive immigrants were assumed to have been exposed to the virus between 1979 and 1988. As reported previously,4 we estimated the year of infection from the conditional probability of being HIV seropositive but free of AIDS in 1988 using disease progression rates reported for the San Francisco City Clinic.7 This method assumes that the longer a person has been infected the less likely he or she would be free of AIDS at the time of immigration. The estimates were adjusted for the growth of the epidemic by weighting the yearly probability of seroconversion with the annual number of AIDS cases reported to the WHO,8 adjusted for the continent-specific distribution of 1988 immigrants and for reporting delays of 1 year.

Estimation of disease progression and survival In the absence of country-specific data we estimated the number of HIV-positive immigrants LE 15 OCTOBRE 1992

whose disease would progress to AIDS each year using San Francisco data.7 Since rates for progression to AIDS have only beeh reported up to 11 years, the annual rate of progression beyond 1 years was assumed to be that of year 11(3%); thus, we assumed that all HIV-positive immigrants would die within 27 years after seroconversion. To estimate direct health care costs attributable to HIV infection we linked disease progression in HIV-positive immigrants- to the reported decrease in the CD4 count of HIV-positive adults using a log-linear decline;9 the count would decrease from 0.90 x 109/L at the time of seroconversion to 0.19 x 109/L at the time of AIDS development.'0 The time to detection of HIV infection was assumed to be the midpoint between the initial CD4 count and one of 0.50 x 109/L (Fig. 1). Before the count decreased to below 0.67 x 109/L HIV infection was considered to be occult.. b3etween the time of detection of HIV infection and the decrease in the CD4 count to below 0.50 x 109/L no specific treatment would be administered other than periodic tnedical examinations. It was assumed that zidovudine (AZT) would be administered when the CD4 count fell below 0.50 x 109/L and that Pneumocystis carinii pneumonia prophylaxis would be used when the count was below 0.20 x 109/L. Admission to hospital was assumed, to occur only when the count was less than 0.19 x 109/L. Using the decline in the CD4 count we determined the proportion of time spent in each of these four stages of disease (Fig. 1). Since there is a paucity of data on the relation between the time to progression to AIDS and survival following a diagnosis of AIDS, the mean survival time was assumed to be 23.6 months."I

-;

0.50

a

PCP

prophylaxis (3%)

AZT treatment (59%)

HIV infection

Progressidr

over time

AIDS

Fig. 1: Proportion of time spent in various stages of human immunodeficiency virus (HIV) infection according to logarithmic decrease of CD4 count. AZT = zidovudine, PCP = Pneumocystis carinii pneumonia and AIDS = acquired immunodeficiency syndrome. OCTOBER 15, 1992

Determination of secondary HIV transmission Secondary HIV transmission from seropositive immigrants to their sexual partners and from seropositive immigrant women to their offspring was assumed to occur only when immigrants were unaware of their HIV serologic status. In 1988, 51% of all immigrants were women. The proportion of female immigrants who were HIV positive was assutned to be the same as that of women in the countries corresponding to the WHO global patterns of HIV infection. The ratio of infected men to infected women is 10:1 in pattern I countries (North America, Western Europe, Australia and New Zealand)'2 and 1:1 in pattern II countries (Caribbean and sub-Saharan Africa);'3 since the ratio in pattern III countries (all remaining countries) is unknown, we assumed that it was the same as in pattern II countries. All HIV-positive female immigrants were considered to be capable of bearing children. Their fertility rate was considered to be that of women in Canada,'4 adjusted for the reported number of children born to immigrant women compared with those born to nonimmigrant Canadian women.'5 The probability of HIV transmission from mother to infant was assumed to be 30%.16,17 The survival period for HIV-positive infants (5.6 years) was determined on the basis of the actuarial survival rates reported for 95 children in the Bellevue Hospital Centre, New York.'8 The risk of horizontal HIV transmission through sexual contact was estimated from the number of new sexual partners over time and the probability of HIV transmission per partner. Because countryspecific data on sexual practices were unavailable male immigrants with partners of the same sex were assumed to have 4.8 partners per year'9 and those with partners of the opposite sex 0.92 partners per year.20 The mean probability of infecting a susceptible partner was estimated to be 0. 1.21 We assumed that 86% of the HIV-positive male immigrants from pattern I countries had only partners of the same sex and that the remaining 14% had only female partners.22 None of the immigrants were considered to be injection drug users. Using data recently reported by the Kinsey Institute,23 we estimated that 97% of the infected male immigrants from pattern II and III countries would have had only female partners and the remaining 3% would have had partners of the same sex. All infected female immigrants were considered to have only male sexual partners.

Estimation of CHD events We assumed that only people who

were

CAN MED ASSOC J 1992; 147 (8)

free of 1165

clinically detectable CHD (e.g., angina and previous myocardial infarction [MI]) would be allowed to immigrate to Canada. We estimated the number of primary and secondary CHD events and the associated surgical procedures among the immigrants over the 10 years following immigration. To estimate the incidence rate of MI we matched the data for immigrants from 188 countries and territories' with the national CHD mortality rates for 76 countries24 by age and sex. When data were unavailable we used the national mortality rates of neighbouring countries or of those in close geographic proximity after matching for life expectancies. According to the method described by Pisa and Uemura,25 we derived primary MI rates from national CHD mortality rates using the age-specific and sex-specific incidence rates of MI from the 17 centres of the 1971-72 Myocardial Infarction Community Registers.26 In our analysis sex was not significantly associated with the regression coefficients, and so male and female immigrants were grouped together. Results for immigrants aged 65 to 74 years and those 75 or more were extrapolated from the data for the younger groups. We assumed that the progression to CHD among the immigrants would be similar to that among Canadians. However, in the absence of Canadian data, the rates of primary CHD events such as sudden death, fatal MI, coronary insufficiency and angina were calculated from the age and sex distribution of CHD events in the United States, as determined by Hartunian, Smart and Thompson27 with the use of data from the Framingham study. We excluded non-CHD-related deaths by subtracting the estimated number of CHD-related deaths from the total number of deaths taken from Canadian life tables.24

tal Medical Records Institute (HMRI LOS Database by CMG, Jan. 1, 1987, to Dec. 31, 1988, for fiscal 1989). These procedures included cardiac catheterization, coronary artery bypass grafting (CABG) with and without cardiac catheterization, angioplasty and pacemaker insertion with and without MI or CHF.

Cost analysis We calculated the cost estimates for HIV-related disease and CHD on the basis of (a) the average length of hospital stay and diagnosis-related cost indices according to the case mix group (CMG) classification from the HMRI, using resource intensity weights (RIW),33 (b) an average cost per diem of treatment in Canadian teaching hospitals in 1988 ($498.86)34 and (c) the average physicians' fees and costs of diagnostic tests as provided by the Regie de l'assurance-maladie du Quebec (RAMQ)35'36 and the Ontario Health Insurance Plan (OHIP).37 When hospital costs were not included in the RAMQ or OHIP schedules we translated fully allocated 1988 overhead costs from the Montreal General Hospital (unpublished data) into Ontario cost equivalents using the ratios of per-diem hospital costs and of laboratory unit charges between Quebec and Ontario.34 Daily hospital costs for HIV-positive children were assumed to be 87% greater than those for adults with AIDS. This estimate was derived from the ratio of per-diem costs between Canadian pediatric and adult teaching hospitals.34 All costs were expressed in 1989 Canadian dollars according to the Canadian hospitals' implicit price index (Income and Expenditure, Accounts Division, Statistics Canada: personal communication, 1990). Costs incurred after 1989 were discounted at a rate of 3%4-38 (Tables 1 and 2).

Estimation of recurrent CHD events

Results We estimated the annual risk of secondary CHD events (sudden death, fatal MI, nonfatal MI and congestive heart failure [CHF]) using recurrence rates from the Framingham study.28 We assumed that patients experiencing primary coronary insufficiency had the same risk of a secondary event as those with primary MI.29 We combined the primary and secondary events in each year after immigration to estimate the prevalence of CHD events necessitating admission to hospital. Assuming that in a given year the proportion of surgical procedures for CHD in the immigrant population would be similar to that in the total Canadian population, we calculated the number of specific cardiac procedures required each year using data from Statistics Canada30-32 and the Hospi1166

CAN MED ASSOC J 1992; 147 (8)

HIV infection model Among the 161 929 immigrants who entered Canada in 1988, 484 (0.3%) were estimated to be infected with HIV but free of AIDS (Table 3). The low and high estimates were 330 (0.2%) and 680 (0.4%). Of the 484 HIV-positive immigrants 266 (55.0%) would be expected to have AIDS in the decade following their entry. Between 1989 and 1998 the HIV-positive immigrants would be expected to spend 3977 person-years in various treatment stages of HIV infection (Table 4). Outpatient AZT therapy would account for 54.5% of these person-years and cost $3786 per person-year for a total of $7.2 million. The cost of outpatient and LE I S OCTOBRE 1 992

inpatient AIDS care would be $21 522 for a total of $9.3 million.

per person-

year,

Although 176 HIV-positive immigrants

would

be unaware of their serologic status in the first year after entering Canada, all would have been identified

being HIV positive within 4 years after immigrating. This would represent a total of 330 person-years in the occult stage of HIV infection, during which time 54 nonimmigrants would be infected with HIV through sexual contact (Table 5). as

Table 1: Costs of care for HIV infection and AIDS per patient-year, by treatment stage*

Treatment stage; cost, $

Service Outpatient caret Physicians' visits Laboratory evaluationt Drugs§ Inpatient care Hospital care¶ Physicians' carell Total

Early outpatient monitoring

Outpatient AZT

146 327 -

473

Outpatient

therapy

Outpatient AZT and PCP prophylaxis

and inpatient AIDS care

350 698 2 738

350 115 3 878

350 115 3 878

-

-

-

-

15 250 1 928

3786

4343

21 522

*HIV human immunodeficiency virus, AIDS acquired immunodeficiency syndrome, AZT = zidovudine, PCP = Pneumocystis carinii pneumonia. In all the tables the marginal totals may not add up because of rounding. tFrequencies of outpatient care were based on the US recommendations for the use of AZT.39 tDepending on the disease stage, laboratory evaluation included complete blood count, CD4, C08 and CD3 counts, HLA-DR histocompatibility antigen typing, automated determination of the serum biochemical profile and chest x-ray examination. §The costs of drugs included $2738 per year for AZT at a daily dose of 500 mg (Burroughs Wellcome Canada, September 1990) and $1140 for pentamidine administered by an ultrasonic nebulizer (Royal Victoria Hospital, Montreal, October 1990). ¶Hospital costs were based on 1.5 admissions per patient-year and included the cost of emergency ambulatory care ($45) at each admission. IlThis included emergency assessment at admission, one daily visit by a general practitioner and three daily visits by specialists. =

Table 2: Costs of care for coronary heart disease per patient

Inpatient service; cost, $ Variable

Myocardial infarction (MI), fatal and nonfatal Coronary insufficiency or angina Congestive heart failure (CHF) Sudden death Coronary artery bypass grafting Without catheterization With catheterization Insertion of pacemaker Without Ml or CHF With MlI or CHF Catheterization Angioplasty

Annual outpatient care

Hospital care 7 487

Physicians' care*

3 653 5 799 646

461 292 420 29

15 676 25 026

2 432 2 683

Total 7 948t 3 945t 6 21 9t

675t 18 108 27 709

9 480

702 10 181 977 18 133 2 726 505 3 232 2 726 663 3 389 Outpatient service; cost, $ Laboratory tests Physicians' and drugs§ Total carel 172 423 595 17 156

*The cost for medical care included one daily visit by a general practitioner and one by a cardiologist; surgical medical costs plus the costs of the surgeon, the anesthesiologist and the radiologist. tHalf of the patients with Ml, coronary insufficiency or angina, or CHF were assumed to require emergency transportation ($154), but all were thought to require hospital emergency department care ($492). tin half of the cases of sudden death the patients were assumed to require emergency transportation and hospital emergency department care; the rest would die at home. §Laboratory tests ($69) included annual chest x-ray examination, electrocardiography and lipid profile tests, as well as semiannual automated determination of the serum biochemical profile. Costs of drugs were estimated to be $354 on the basis of data from Intemational Medical Surveillance of Canada.40 ¶This included three visits by a general practitioner and two consultations with a cardiologist. cases included

OCTOBER 15, 1992

CAN MED ASSOC J 1992; 147 (8)

1167

..l

HIV-positive female immigrants would account for 135 person-years in the occult stage; during this time they would give birth to 1.9 HIV-positive infants (Table 5). After discounting, we estimated that the total direct health care cost attributable to HIV infection would be $18.5 million (extremes $12.6 and $26.1 million): $17.1 million (extremes $11.7 and $24.1 million) for the care of the HIV-positive immigrants, $1.0 million (extremes $0.7 and $1.5 million) for the care of their nonimmigrant, HIV-positive sexual

partners and $0.4 million (extremes $0.3 and $0.5 million) for the care of the HIV-positive children born to seropositive immigrant women.

CHD model Between 1989 and 1998, 2558 (1.6%) of the immigrants would be expected to experience at least one primary CHD event. In addition, they would experience 651 recurrent CHD events and require 984 surgical procedures.

Tabie 3: Estimatec number of HIV-pc;r:ir ve oeopeIE amnct,-;, mrnilgrants entering Canada in 1988 No (and O) i mrmigrants

I,Ctrnt nent

W10-positive 'mmimgrantl (`41(and %;tO I Range

28 902 (18) 9 887 (6) 40 351 (25) 83 474 (50)

Ameerica Africa L. 'Li r 0 D C.-

Asia .V'eania 'V. t

200 (41)

154-258 1 7t -240: 30-99 277--7Q_

(36)

59 ' 1t 2) d8 1 )

i .- .

,..'

6.1 929 1 00)

484 1 001

330o--680

fable 4: Number of person-year-s anol Losts, ne^curred over 1 (vear among the estimated 484 HIV-positrvr mm rr grarits.t by treatment stag e Total cost

r-reatment stage Iccuit d:isease

Early outpatient monitoriinu, Jutpatient AZT therapy

:O)utpatient AZT and PCP prophylaxis

No. of person-years (and range)

r0.67 0.90' 0.50 5--- 0., h 0.20- 0 5.0

330 (225-464i 908 (619--.12g. 2 166 (1 476 3QL46

i i9

Outpatient and inpatient A[)DS care ,.

." D4 Cu urt> 10 IL

.-i

71 (4810---0 0

Sr i?t

r- i _c

'Al

502 (342--- 0? 977 (2710 f-jr44. {

.aDble 5: Secondary HIV transrminsslon, frorm thel estimated 484 HIV-positive

Horizorntai HPV tranrsmlssIor, No. ui

person-years spent '1990 11991z

in occult stage

o. iut nrewly infected rartnerc

'176 (120-247' 96 (66--135) 45 (31-64) 12 (88 i17

29 (.20--42) 1 6 (1 -23) (5 1 ) i1. 3

995

1.'94 1995

0 0IJ 0

1a997 1.998

1168

r:is--

,

l parenthesis

reter

to;

ranges around

CAN MED ASSOC J 1992; 147 (8)

3 786

0 (0) 0.4 (0.3-0.6, 7.2 (4.9-10.1

4 34 3

0.3 (0.2- 04)

2 1 5 22

9.3 (6.3---- 13

immigrants over 10 years*

Vertical HIV transmission No. of HIV-positive children born to Person-years spent

it- cccl't stage 72 39 18 5

(49-100) (27--55) (13-26) (3 -7-

0

f-' i

54 (37 78)

(and range), million $

17.1 (11 7-

0e_.

0 330 (225 --464)

Oti !I

0

Cost per patient-year. $

135 (91-187)

'HIV-positive immigrant woimenr1.0 (0.7-1.4) 0.6 (0.4-0.8) 0.3 (0.2- 04) 0.1 (0.0-0.1) 0 0 0 0 0 0 1-9 (1.3-2.6)1

precedinqi coont estimates

LE 15 OCTOBRE 1992

Among the 1226 MI events 819 would be primary (133 fatal and 686 nonfatal) and 407 secondary (170 fatal and 237 nonfatal). At a cost of $7948 per MI, $8.4 million (39%) of the total direct care costs would be spent on treating MI alone (Tdble 6). Of the 1160 immigrants with primary angina, only 58 (5.0%) would have to be admitted to hospital; the cost of outpatient follow-up care for the remaining 1102 immigrants with angina and all survivors of CHD events would be $595 per year, for a total of $4.4 million. Surgical interventions, accounting for 30% of the total direct care cost, would cost $6.5 million, of which $3.2 million would be for CABG. By 1998, $21.6 million would be spent on caring for immigrants with CHD; $17.2 million (79.6%) would be for hospital costs and $4.4 million (20.4%) for outpatient care. Immigrants 50 years of age or more in 1988 would be expected to incur $14.0 million (64.8%) of the total cost.

Discussion Our analysis demonstrates that from the point of view of the national health care system the economic impact of HIV infection in immigrants to Canada would be similar to that of CHD ($18.5 million v. $21.6 million respectively). In any economic model there exist assumptions and estimates open to question. We limited the time horizon of our study to 10 years, because extending

it further would have increased the uncertainty surrounding many of our estimates and the present value of discounted costs in the distant future would have minimal impact on our final results. On the other hand, the source-mix of immigrants may change over time. This, combined with potential changes in HIV seroprevalence data in the source countries, could alter the aggregate costs of HIV infection in people immigrating to Canada after 1988. In our calculations we did not exclude HIVpositive immigrants who died of causes other than HIV-related disease, primarily because the age distribution of the HIV-positive immigrants is unknown. However, if we assume that the age distribution for the HIV-positive immigrants is the same as that for all the 1988 immigrants, according to the Canadian life tables,24 the all-cause mortality rate over the 10 years would be no more than 6% among the HIVpositive immigrants. Since the peak age at which people acquire HIV infection is 15 to 49 years, an age group that accounts for 64% of the immigrants, the rate of death from non-HIV-related causes would be considerably less than 6% (27 deaths). We assumed that AIDS would develop in all HIV-positive people within 27 years after immigration. This corresponds to the estimates of Lemp and associates.41 Recent trends in survival among AIDS patients treated with AZT4243 confirm the projected mean survival of 23.6 months used in our analysis.

Table 6: Cost of coronary heart disease among the 161 929 immigrants over 10 years, by event Total cost Event

Inpatient care Ml

Coronary insufficiency CHF Angina Sudden death* Coronary artery bypass grafting Without catheterization With catheterization Insertion of pacemaker Without Ml or CHF With Ml or CHF

Catheterization Angioplasty Outpatient care Angina Follow-up care Total cost

Unit cost, $

(and %), in million $

169 58 167

7 948 3 945 6 219 3 945 675

8.4 (39) 1.1 (5) 0.9 (4) 0.2 (1) 0.1 (0)

145 39

18 108 27 709

2.3 (10) 0.9 (4)

151 28 510 110

10 181 18 133 3 232 3 389

1.3 0.3 1.4 0.3

No. of patients 1 226 317

1 102 7 781t

595t 595t

(6) (1) (6) (1)

0.6 (3) 3.8 (18) 21.6 (100)

In the 334 cases of sudden death 167 patients (50%) were expected to die in the emergency department. tCost per year. tNumber of person-years.

OCTOBER 15, 1992

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1169

The estimate that 0.3% of the immigrants to Canada in 1988 would be HIV positive is similar to the proportion of applicants for immigration to the United States who were found to be seropositive through HIV antibody screening.3'6 Despite great regional variation, it is also similar to global estimates reported by the WHO.44 In the analysis of progression from HIV infection to AIDS the average log-linear decrease in the CD4 count was similar to estimates by Brundage and collaborators.9 However, if we use a linear model instead, as suggested by Moss and colleagues,45 the total cost of HIV-related treatment would decrease by 11%, to $16.6 million. Estimates of the number of sexual partners were taken from a British survey.'9'20 If these estimates were decreased or increased by 50%, the expected total care cost would be from $18.0 to $19.1 million, a change of only 3% from the original estimate. Data on the probability of HIV transmission between sexual partners are limited, reported estimates ranging between 0.1 and 0.6 per partner.'9 We used the lower value; using the higher value would increase the expected total HIV treatment cost by 28%, from $18.5 to $23.7 million. Our MI estimates from the CHD model were similar to empiric data from the WHO project on Monitoring Trends and Determinants in Cardiovascular Disease in Russia,46 China,47 Czechoslovakia48 and Poland,49 as well as estimates from Australia,50 Brazil5' and Honolulu.52 In both the HIV infection and the CHD models we estimated the cost per patient-year or per CHD event, respectively, using CMG data provided by the HMRI. Since hospital deaths were excluded our unit costs do not capture the total hospital experience for either group of patients. Nevertheless, our HIV cost estimates compared favourably with those from recent studies,53-55 as did our CHD cost estimates per

event.56-60 We did not attempt to match the economic contributions (income, savings, taxes) of immigrants against their health care costs. There is a de-facto annual quota for immigrants and a permanent backlog of applicants.6",62 We therefore assumed that equally qualified immigrants would be immediately available to replace candidates excluded for health reasons.

Conclusions We have demonstrated that there are some economic savings to the health care system associated with mandatory HIV antibody screening of immigrants to Canada. However, HIV infection is not the only condition that poses a financial burden. The impact of CHD, in terms of both the number of 1170

CAN MED ASSOC J 1992; 147 (8)

people affected and the associated health care costs, would be at least equal to the impact of HIV infection. Our cost comparison identifies the problems inherent in developing immigration policy around considerations of health care economics. Screening for any disease that is both ubiquitous and costly could potentially save money, especially if the costs of screening were borne by potential immigrants. Accordingly, the implementation of such an immigration policy demands that we determine which diseases pose the greatest economic threat to the national health care system. Our analysis confirms that some of the economic burden of HIV infection could be avoided if immigration authorities imposed mandatory HIV antibody screening on all immigrants. However, if such a decision is based on economic considerations, one must conclude from our cost comparison that a policy for CHD screening should be developed as well. The government has a public responsibility to protect the welfare of its citizens. Our estimates of horizontal HIV transmission suggest that between 37 and 78 partners of HIV-positive immigrants would eventually become infected over the 10 years after immigration. Some of these partners would have been residents of Canada before 1989, and one could argue that immigration policy had not protected their interests. However, most cases of HIV transmission occur through unprotected sexual intercourse, for which the individual is solely responsible. Moreover, the risk of HIV infection must be compared with the risk of other infectious diseases currently not screened for, including viral hepatitis. We conclude that immigration policy regarding HIV infection must be based on a number of considerations, including the competing risks and associated costs of other common diseases. To focus only on HIV infection is arbitrary at best and discriminatory at worst. If the goal of immigration officials is to protect the public welfare and to ensure the solvency of the health care system, similar cost analyses for other common illnesses will be necessary before HIV antibody screening is implemented. Once such analyses are completed, important social, legal and ethical considerations must then be addressed if the final policy is to reflect both the goals of our government and the values of our society. We thank Joel Finlay, director general of the Federal Centre for AIDS, Ottawa, Dr. Normand Lapointe, H6pital Sainte-Justine, Montreal, and Dr. Neil Heywood, Department of National Health and Welfare, Ottawa, for their helpful comments during the analysis of this study. We also thank Nadine Bouchard for her assistance in preparing the manuscript. This study was supported by grant 6605-2938-AIDS from the National Health Research and Development LE 15 OCT^OBRE 1992

Program, Department of National Health and Welfare. Drs. Gilmore and Grover are research scholars supported by the Fonds de la recherche en sante du Quebec.

References 1. Gilmore N, Orkin AJ, Duckett M et al: International travel and AIDS. AIDS 1989; 3 (suppl 1): S225-S231 2. Somerville MA: The case against HIV antibody testing of refugees and immigrants. Can Med Assoc J 1989; 141: 889894 3. Gostin LO, Cleary PD, Mayer KH et al: Screening immigrants and international travellers for the human immunodeficiency virus. N Engl J Med 1990; 322: 1743-1746 4. Zowall H, Fraser RD, Gilmore N et al: HIV antibody screening among immigrants: a cost-benefit analysis. Can Med Assoc J 1990; 143: 101-107 5. Immigration Statistics, Employment and Immigration Canada, Hull, Que, 1989 6. Studemeister A, Westling R, Kent G: HIV infection among immigrants to the United States [abstr FC.547]. Paper presented at the 6th International Conference on AIDS, San Francisco, June 20-24, 1990 7. Lifson AR, Hessol N, Rutherford G et al: Natural history of HIV infection in a cohort of homosexual and bisexual men: clinical and immunologic outcome, 1977-1990 [abstr Th.C.33]. Ibid 8. Update: AIDS Cases Reported to Surveillance, Forecasting and Impact Assessment Unit, Global Program on AIDS, WHO, Geneva, 1989 9. Brundage J, Gardner L, McNeil J et al: Progression of HIV disease during the early stages: estimating rates of decline of CD4+ T-lymphocytes [abstr Th.C.6281. Paper presented at the 6th International Conference on AIDS, San Francisco, June 20-24, 1990 10. Lang W, Perkins H, Anderson RE et al: Patterns of T lymphocyte changes with human immunodeficiency virus infection: from seroconversion to the development of AIDS. JAIDS 1989; 2: 63-69 11. Longini IM Jr, Clark SW, Byers RH et al: Statistical analysis of the stages of HIV infection using a Markov model. Stat Med 1989; 8: 831-843 12. Sato PA, Chin J, Mann JM: Review of AIDS and HIV infection: global epidemiology and statistics. AIDS 1989; 3 (suppl 1): S301-S307 13. Chin J, Mann JM: The global patterns and prevalence of AIDS and HIV infection. AIDS 1988; 2 (suppl 1): S247-S252 14. Wadhera S: Trends in birth and fertility rates, Canada, 1921 1987. Health Rep 1989; 1: 211-223 15. Canada's Immigrants (cat no 99-936), Statistics Canada, Ottawa, 1984 16. Blanche S, Rouzioux C, Guihard Moscato ML et al: A prospective study of infants born to women seropositive for human immunodeficiency virus type 1. N Engl J Med 1989; 320: 1643-1648 17. Chin J: Current and future dimensions of the HIV/AIDS pandemic in women and children. Lancet 1990; 336: 221-224 18. Krasinski K, Borkowsky W, Holzman RS: Prognosis of human immunodeficiency virus infection in children and adolescents. Pediatr Infect Dis J 1989; 8: 216-220 19. Anderson RM, Blythe SP, Gupta S et al: The transmission dynamics of the human immunodeficiency virus type I in the male homosexual community in the United Kingdom: the influence of changes in sexual behaviour. Philos Trans R Soc Lond/Biol] 1989; 325: 7-60 20. Anderson RM, May RM: Epidemiological parameters of HIV transmission. Nature 1988; 333: 514-519 21. Anderson RM, Medley GF: Epidemiology of HIV infection and AIDS: incubation and infectious periods, survival and vertical transmission. AIDS 1988; 2 (suppl 1): S57-S63 OCTOBER 15, 1992

22. HIV/AIDS Surveillance Report, US Centers for Disease Control, Dept of Health and Human Services, Bethesda, Md, 1989: 1-16 23. Fay RE, Turner CF, Klassen AD et al: Prevalence and patterns of same-gender sexual contact among men. Science 1989; 243: 338-348 24. World Health Statistics, 1988 (annual), WHO, Geneva, 1988 25. Pisa Z, Uemura K: Trends of mortality from ischaemic heart disease and other cardiovascular diseases in 27 countries, 1968-1977. World Health Stat Q 1982; 35 (1): 11-47 26. Myocardial Infarction Community Registers: Results of a WHO International Collaborative Study Coordinated by the Regional Office for Europe, WHO Regional Office for Europe, Copenhagen, 1976 27. Hartunian NS, Smart CN, Thompson MS: The Incidence and Economic Costs of Major Health Impairments. A Comparative Analysis of Cancer, Motor Vehicle Injuries, Coronary Heart Disease, and Stroke, Lexington Bk, Lexington, Mass, 1981: Table 3-3 28. Kannel WB, Gordon T (eds): The Framingham Study: an Epidemiological Investigation of Cardiovascular Disease (DHEW publ no [NIH] 88-2969), National Institutes of Health, Bethesda, Md, 1988 29. Mulcahy R, Al Awadhi AH, de Buitleor M et al: Natural history and prognosis of unstable angina. Am Heart J 1985; 109: 753-758 30. Hospital morbidity. Health Rep 1989; 1 (suppl): Table 2 31. Peters S, Chagani K, Paddon P et al: Coronary artery bypass surgery in Canada. Health Rep 1990; 2: 9-26 32. Surgical procedures and treatments. Health Rep 1989; 1 (suppl): Table 2 33. Carmichael D: Case Weighting Methods: a Review by the HMRI Database Committee, Hospital Medical Records Institute, Don Mills, Ont, 1988 34. Hospital statistics preliminary annual report. Health Rep 1989; 1 (suppl): Table 16 35. Manuel des medecins omnipraticiens, Regie d'assurance-maladie du Quebec, Quebec, 1989 36. Manuel des medecins specialistes, Regie d'assurance-maladie du Quebec, Quebec, 1989 37. Schedule of Benefits, Physician Services Under the Health Insurance Act, Ont Ministry of Health, Toronto, 1989 38. Oster G, Epstein AM: Primary prevention and coronary heart disease: the economic benefits of lowering serum cholesterol. Am JPublic Health 1986; 76: 647-656 39. Recommendations for zidovudine: early infection. JAMA 1990; 263: 1606-1609 40. International Medical Surveillance of Canada, Canadian CompuScript, 1989 41. Lemp GF, Payne SF, Rutherford GW et al: Projections of AIDS morbidity and mortality in San Francisco. JAMA 1990; 263: 1497-1501 42. Moore RD, Hidalgo J, Sugland BW et al: Zidovudine and the natural history of the acquired immunodeficiency syndrome. NEngl JMed 1991; 324: 1412-1416 43. Peters BS, Beck EJ, Coleman DG et al: Changing disease patterns in patients with AIDS in a referral centre in the United Kingdom: the changing face of AIDS. BMJ 1991; 302: 203-207 44. Chin J: Global estimates of AIDS cases and HIV infections: 1990. AIDS 1990; 4 (suppl 1): S277-S283 45. Moss AR, Bacchetti P, Osmond D et al: Seropositivity for HIV and the development of AIDS or AIDS related condition: three year follow up of the San Francisco General Hospital cohort. BMJ 1988; 296: 745-750 46. Varlamova T, Zhukovski G, Chazova L et al: Monitoring of major cardiovascular diseases in Moscow, USSR. Acta Med Scand Suppl 1988; 728: 73-78 47. Wu ZS, Yao CH, Chen DY et al: The sino-MONICA-Beijing study: report on results between 1984 and 1986. Ibid: 60-66 48. Skodova Z, Pisa Z, Hejl Z et al: Coronary events in the CAN MED ASSOC J 1992; 147 (8)

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population of six districts of the Czech socialist republic. Cor Vasa 1988; 30: 324-330 Rywik S, Kupsc W, Wagrowska H et al: Mortality, morbidity and case fatality from myocardial infarction and the cardiovascular risk profile in the Warsaw population. Acta Med Scand Suppl 1988; 728: 95-105 Reznik RB, Goldstein GB, Ring I et al: The determination of the incidence of acute myocardial infarction from hospital morbidity records. J Chronic Dis 1984; 37: 733-742 Lessa I, Cortes E, Souza JA et al: Epidemiology of acute myocardial infarction in Salvador, Brazil: I. Incidence, lethality, and mortality. PAHO Bull 1987; 21 (1): 28-36 Gordon T, Garcia-Palmieri MR, Kagan A et al: Differences in coronary heart disease in Framingham, Honolulu and Puerto Rico. J Chronic Dis 1974; 27: 329-344 Arno PS, Shenson D, Siegel NF et al: Economic and policy implications of early intervention in HIV disease. JAMA 1989; 262: 1493-1498 Andrulis DP, Beers Weslowski V: Hospital trends and the financing of medical care for AIDS patients. In Le Vee WN (ed): Conference Proceedings. New Perspectives on HIV-related Illnesses: Progress in Health Services Research, Miami, May 17-19, 1989, US Dept of Health and Human Services, Washington, 1989: 58-69

Conferences

continued from page 1137 Nov. 13-15, 1992: Advanced Neurological Life Support Course Toronto Northwestern Hospital Arlene Murray, course coordinator, PO Box 261, Sharon, ON LOG IVO; (416) 478-4002 Nov. 13-15, 1992: Quebec Association of Urologists 7th Annual Meeting Four Seasons Hotel, Montreal Ms. Jacqueline Deschenes, Quebec Association of Urologists, 3000-2 Complexe Desjardins, east tower, Montreal, PQ H5B I G8; (514) 350-5131, fax (514) 350-5181

Nov. 16-18, 1992: Excellence in Medical and Scientific Writing Toronto McLuhan and Davies Communications, Inc., 167 Carlton St., Toronto, ON M5A 2K3; (416) 967-7481, fax (416) 967-0646 Nov. 17-19, 1992: Royal Postgraduate Medical School (RPMS) Institute of Obstetrics and Gynaecology Course Obstetric Anaesthesia and Analgesia Queen Charlotte's and Chelsea Hospital, London Symposium secretary, RPMS Institute of Obstetrics and Gynaecology, Queen Charlotte's and Chelsea Hospital, Goldhawk Road, London W6 OXG; telephone 01 -44- 1 081-740-3904, fax 01-44-1-081-741-1838 Nov. 19-21, 1992: College of Family Physicians of Canada (BC Chapter) 5th Annual Conference - The Diversity of Family Practice Four Seasons Hotel, Vancouver 1172

CAN MED ASSOC J 1992; 147 (8)

55. Scitovsky A: Past lessons and future directions: the economics of health services delivery for HIV-related illnesses. Ibid: 21 33 56. Sawitz E, Showstack JA, Chow J et al: The use of in-hospital physician services for acute myocardial infarction. Changes in volume and complexity over time. JAMA 1988; 259: 24192422 57. Barbash GI, Safran C, Ransil BJ et al: Need for better severity indexes of acute myocardial infarction under diagnosis-related groups. Am J Cardiol 1987; 59: 1052-1056 58. Black AJR, Roubin GS, Sutor C et al: Comparative costs of percutaneous transluminal coronary angioplasty and coronary artery bypass grafting in multivessel coronary artery disease. Am J Cardiol 1988; 62: 809-811 59. Cohen HA, Solnick M, Stephenson A: The financing of coronary artery bypass surgery. Circulation 1982; 66 (suppl 3): III-49-111-55 60. Fuchs VR, Hahn JS: How does Canada do it? A comparison of expenditures for physicians' services in the United States and Canada. N Engl J Med 1990; 323: 884-890 61. Annual Report to Parliament on Future Immigration Levels, Employment and Immigration Canada, Hull, Que, 1989 62. Backlog Clearance Process (press release 89-05), Employment and Immigration Canada, Hull, Que, 1989

Mrs. Pat Muss, BC Chapter, College of Family Physicians of Canada, 350-1665 W Broadway, Vancouver, BC V6J lXI; (604) 736-6400, fax (604) 736-4675 Dec. 9, 1992: Computer Based Records Supporting Patient Care Management Seminar Regal Constellation, Toronto CME credits available. Heather Pastorchik, conference coordinator, Computer Based Records Supporting Patient Care Management, c/o Clinicare Corporation, 4306-1Oth St. NE, Calgary, AB T2E 6K3; (403) 291-3949, fax (403) 250-8950

Dec. 10, 1992: Computer Based Records Supporting Patient Care Management Seminar Chateau Laurier Hotel, Ottawa CME credits available. Heather Pastorchik, conference coordinator, Computer Based Records Supporting Patient Care Management, c/o Clinicare Corporation, 4306-10th St. NE, Calgary, AB T2E 6K3; (403) 291-3949, fax (403) 250-8950

Jan. 29-30, 1993: HIV Symposium - a Multidisciplinary Approach Sheraton Hotel, Hamilton Continuing Education, Faculty of Health Sciences, McMaster University - Chedoke Campus, TB74- 1200 Main St. W, Hamilton, ON L8N 3Z5; (416) 521-7966, fax (416) 389-4224

Jan. 29-30, 1993: Sport Med '93 - Annual Sports Medicine Symposium (sponsored by the Ontario Medical Association's Section on Sports Medicine) Holiday Inn Crowne Plaza, Toronto Airport Ms. Erna Walker or Ms. Susan Teslak, meetings planning, Ontario Medical Association; (416) 599-2580 or

1-800-268-7215 For prescribing information see page 1277 -