SPECIAL A R T I C L E
ROUTE OF ADMISSION AND HOSPITAL COSTS FOR UROLOGIC PATIENTS ERIC MUNOZ, M.D., M.B.A. JON R. COHEN, M.D. ALAN DIETZEK, M.D.
KATHERINE MULLOY IRVING B. MARGOLIS, M.D. LESLIE WISE, M.D.
From the Department of Surgery, Queens Hospital Center, Jamaica, New York, and the Long Island Jewish Medical Center, New Hyde Park, New York, and the State University of New York, Stonybrook, New York
A B S T R A C T This study of 2,549 urology patients examined resource consumptiort i:,¢ ro,,l~:e Of admission into the hospital. Almost all urologic admissions were more expens~:ve as e:,~erg~~.:~c~es. These more expensive emergency urologic admissions had higher diagnostic costs, a lo'nge~ h~,.!ip~~al length of stay, and a greater severity of illness than their less expensive non-emergency cr~z::~iIeq:~oft. The more expensive emergency admission had a high referral rate to urology from non.ur,:m,lo:!'ie clinical services. These findings suggest that efficiency might be improved in the emer~:enc~1 u-'ologic patients by increasing the speed of diagnosis and admission of patients to the aplproi,:,'id~te, clinical service (urology).
Payment changes underway for the reimbursement of hospitals and physicians will cause physicians to study methods to improve efficiency. Our group has been interested in route of admission (i.e., emergency vs nonemergeney) characteristics for groups of hospitalized patients. Two findings seem applicable from a number of our studies eoneerning the Medicare Diagnostic Related Group (DRG) prospective hospital payment system, i.e., emergency admissions may tend to generate financial risk under DRG, and emergency admissions are usually more costly per DRG than their nonemergency counterpart. 2'a The purpose of this study was to more precisely quantify resource consumption for urology patients by route of admission into the hospital. Important parameters measured were total hospital costs, hospital length of stay, diagnostic costs, severity of illness, and change in clinical service, i.e., referral to urology service from another elinical service.
548
Material and Methods
Study design We determined which DRGs had 15or :more patients admitted through the emergency room (ER) and 5 or more patients not admitted through the ER, and at least 1,0 19e:~cent or more of the total DRG population admitted through the ER. Patients in those DRCs whicl~ fit the aforementioned criteria were inchltde~3in the study (N = 2,549). The DRGs were div:ided into two groups. Costs for patients wIao were admitted through the ER were higher than for those who were not admitted through the ER (ER > non-ER), and DRG costs for patients who were admitted through the ER were tess than for patients who were net admRted through the ER (non-ER > ER). Analytic comparisons All adult urology patients fitting the study design during 1985 and 1986 were analyzed. UROLOGY
/
JUNE i990
VOLUME XXXV, NUMBEtR 0
TABLE I.
Besource characteristics (mean~patient): EB > non-ER and non-EB > EB
--ER > Non-ER EI1 Non-ER 361 1,911 1.1535" 1.2344 12.0~ 7.4 $9,122~ $6,410 $1,69511 $1,178 6.1% II 1.6 % ($1,456) ~ $1,465 2.66~ 2.14 2.93 2.78 5.59 4.93 1.4 % 1.2 %
Characteristic Sample size DItG wt. index (mean) Hosp. length (days) Total costs Diagn. costs Outliers DRG profit/ (loss) No. of diagn.¶ No. of procedures~[ Total severity~[ Mortality
Non-ER > El( ER Non-ER 147 i31 0.7326 0.7426 4.65 6.5 $3,604§ $5,286 $7665 $1,005 0.7 % 1.5 % $1,680§ $66 1.98 "2.12 1.03§ 1.97 3.02 4.09 0.7 % 0%
*Star. diff. at p < 0.03 from non-ER category. tStat, diff. at p < 0.0001 from non-ER category. ~:Stat. diff. at p < 0.05 from non-Ell category. §Star, diff. at p < 0.002 from non-Ell category. IlProfit/loss under DtlGs: parentheses = loss. ~Number of ICD-9-CM eodes/patient.
Our hospital costing methodology is a stepdown alloeative method contained on our Medicare cost report and outlined in other works. 4 Diagnostic costs were computed as a total of laboratory costs (urinalysis, hematology, coagulation, biochemistry, and microbiology) and diagnostic radiology costs. The total number of ICD-9-CM (International Classification of Diseases [9th Rev.] Clinical Modification) diagnoses and procedure codes per patient at discharge were used as a proxy for severity of illness. A change in service was described as admission to other than the discharging service, i.e., urology. A number of parameters were analyzed per patient for both ER and non-ER groups including: total hospital cost, hospital cost by hospital service (room and board, laboratory, radiology, blood, operating room-recovery room, central supply-pharmacy, and other), the mean DRG weight index, the hospital length of stay (LOS) in days, percent outliers, profit or loss under D R G r e i m b u r s e m e n t , n u m b e r of ICD-9diagnoses codes, number of ICD-9-CM procedure codes, and mortality. Data were computed as a mean per patient _+ standard deviation. Student's t test was used to test for statistical significance between groups of patients. Results The 2,272 admissions in the ER > non-ER category generated $15,542,284 in total hospital costs, $3,292,983 for the 361 ER admissions, and $12,249,300 for the 1,911 non-ER admissions. The 278 admissions in the non-ER > Etl
UROLOGY
/
JUNE 1990
/
VOLUME XXXV, NUMBER 8
I'V'~ L SO
lut-
"55.82_ i
2g
qq. 7
29.q ig
IIII I
:roT.az co$~'B
]
n~RCTY
MR OREalrERTH*N HOIC-ER
i
O g ZL£*VBB$
[]
DZaOHO~rrlC C0$cr5 lqt~H-NR
IIR~RTEIqTHOleI~R
FICURE 1.
Components of higher costs: for EB > non-EB diagnostic costs, total costs, and severity of illness were higher for EB admissions. Non-Etl > ER displayed same characteristics with total costs and severity more so, and diagnostic costs less so.
category generated $1,222,165 in total hospital costs: $529,751 for the 147 ER admissions, and $692,414 for the 131 non-ER admissions. For the entire 2,549 study population, 89.1 percent of patients were admitted in the DRG group and per patient ER costs were greater than nonER costs (10.9%). The higher costs of the ER > non-ER category were associated with a 36.7 percent greater total hospital cost, a 21.6 percent greater severity of illness, and a 53.8 percent greater diagnostic cost (all 3 corrected for DRG weight index) (Fig. 1). Aggregate characteristics of the Ell > non-ER category are shown in Table I. ER admissions had a 6.5 percent 549
f
smaller mean DllG weight index compared with non-Eli admissions, but they had a 42.3 percent greater total hospital cost per patient, a 66.2 percent greater hospital length of stay, and a 43.8 percent greater diagnostic cost. In addi~ tion, the percent outliers, the financial risk, the number of ICD-9-CM diagnoses and procedure codes, and the mortality were higher for Et{ compared with non-EB admissions. The greater the cost of the non-EI/ > Ell category was associated with a 44.7 percent greater total hospital cost, a 34.0 percent greater severity of illness, and a 29.4 percent greater diagnostic cost (all 3 corrected for DllG weight index) (Fig. 1). Aggregate characteristics of the non-Eli > Eli category are shown in TaMe Io Non-Ell admissions had a 1.4 percent greater DllG weight index than EB admissions; they had 44,7 percent greater total hospital cost per patient, a 40.1 percent greater hospital length of stay, and 31.2 percent greater diagnostic cost. Although non-ER admissions had higher resource utilization, greater financial risk, and a greater severity of illness than ER admissions in this category, the differences were less striking than in the ER > non-ER group. Change in clinical service was highest for Eli admissions in the EB > non-Ell category (18 of 361 patients), non-ER admissions in this category demonstrated that 3 0 o f 1,911 changed clinical service (p < 0.005) (Fig. 2). In the nonEll > Ell category, non-Ell admissions generated I of 131 patients with a change in clinical service, whereas for Ell admissions in this
group 4 of 147 changed clinical service (p = N.S.). Comment The purpose of this study was to analyze hospital resource consumption for urology patients by route of admission into the hospital. Almost all emergency urology admissions were more costly than nonemergeney admissions. Emer, gency urologic admissions had higher diagnostic costs, a longer hospital stay, and a greater severity of illness than their less expensive nonemergency counterparts. The small group of patients where nonemergeney admissions were more costly than emergency admissions demonstrated these same trends. These findings may offer opportunities to improve efficiency for urology patients. Our data suggest that total hospital costs might be reduced for the more expensive emergency urologic patient by increasing tile speed of diagnosis, possibly by examining the sequence and timing of preoperative testing for these patients. One study by our group of emergency surgical admissions undergoing eholecystectomy suggested that the diagnostic costs for these patients were much higher than those for nonemergency surgical patients undergoing choiecystectomy. 5 This current study defines these higher diagnostic costs more precisely. In another study by our group we examined the preoperative length of stay for emergency surgical patients undergoing other common general surgical procedures. Emergency general surgical admissions tended to have relatively long preoperative lengths of stay. 6 This study suggested that total costs might be reduced in ~his population by increasing the speed of diagnostic testing and facilitating operative scheduling to avoid delays. It is possible that efficiency may be improved for the emergency urologic admission, but further study will be needed along these lines. The change in clinical service findings of this study may be important for both cost containment and quality assurance. The more expensive emergency urologic admission had the greatest rate in change in clinical service (i.e,, referred to urology from another clinical service). One of our previous studies had suggested that a chang e in clinical service was associated with higher hospital costs. 7 We studied patients undergoing craniotomy (i.e., DBG 1) and found that patients referrec} to neurosurgery for craniotomy had much higher costs than nonreferred patients. Many of these more expensive
550
UROLOGY
~T
°E ]
!
,I, HR OR~TE~'THnHXOH-ER
L'RP,eT2"/~'M~.5"
HOCl-.ER OR1E,ffTBR THOle ~EI~
]
lgOH-2~RP,~TI,EJq"f$
FIaURE 2. Change in clinical service was greatest for emergency admission in the EB > non-EB category.
/ JUNE 1990
/
VOLUME XXXVo NUMBEI~ 6
referred craniotomy patients were admitted to the neurology service, then much later in their hospital stay referred to neurosurgery for eraniotomy. This craniotomy study did suggest that, if possible, admission to the appropriate clinical service might improve efficiency. Change in clinical service also may be of interest to those in the hospital sector focusing on quality assurance. We have studied a small group of patients referred to the general surgical service from the medical service, vis-a-vis their quality of care. 8 Referred patients were more likely to have deficiencies in quality of care than nonreferred patients. Thus referred patients were more likely to suffer errors in diagnosis and/or management, or delays in surgery, compared with nonreferred patients. It is possible that referred urologic patients may be more "vulnerable" to quality-of-care deficiencies. Further study will be needed along these lines. This study demonstrated that route of admission into the hospital may provide similar cost characteristics between groups of patients. It is possible that the study of these characteristics may offer opportunities to improve efficiency. Long after the era of hospital prospective DRG payment has ended, route of admission should offer opportunities to improve efficiency. The urologist will need to meet the challenge of the future, i.e., meeting "unlimited" demands with "limited" resources.
UROLOGY / JUNE 1990 /
VOLUMEXXXV, NUMBER 6
Department of Surgery Long Island Jewish Medical Center New Hyde Park, New York 11042
(DR, MUNOZ) ACKNOWLEDGMENT:To James Moyer, Seth Warren, and Gordan Doletto of the Divisions of Management Information Systems, and the DRC Task Force of the Long Island Jewish Medical Center, and Jonathan Coldstein for their data computation, and to Christina Weiss for assistance in the preparation of this manuscript.
References 1. Blendon RJ: Policy choices for the 1990s: an uncertain look into America's future, in Cinzberg E: The US Health Care System. A look to the 1990s, Totowa, N.J., Rowman & AUanheld, 1985. 2. Munoz E, et ah The financial effect of emergency room generated admissions under prospective payment systems, JAMA 254: 1763 (1985}. 3. Munoz E, Tinker MA, Margolis I, and Wise L: Surgonomics: the identifier concept. Hospital charges in general surgery and surgical subspecialfies, Ann Surg 202:119 (1985). 4. Munoz E, Margolis IB, and Wise L: Surgonomics: the cost demographics of choleeysteetomy, in Virgo J (Ed): Restructuring Health Policy: An International Challenge, Evansville, Ill., International Health Economies and Management Institute, 1986, pp 329-340. 5. Munoz E, Tinker MA, Margolis I, and Wise L: Surgonomics: the cost of cholecystectomy, Surgery 96:642 (1984). 6. Munoz E, et ah T h e identifier concept: clinical variables to manage costs for surgical patients, Hosp Health Serv Admin h 85 (1987). 7. Munoz E, et ah Surgenemics: the cost of craniotomy, Neurosurg 18" 321 (1986). 8. Munoz E, et ah The medical patient referred to general surgery, resource utilization and outcome under DRG reimbursement, Arn J Surg 157:237 (1989L
551
ROUTE OF ADMISSION AND HOSPITAL COSTS FOR UROLOGIC PATIENTS ERIC MUNOZ, M.D., M.B.A. JON R. COHEN, M.D. ALAN DIETZEK, M.D.
KATHERINE MULLOY IRVING B. MARGOLIS, M.D. LESLIE WISE, M.D.
From the Department of Surgery, Queens Hospital Center, Jamaica, New York, and the Long Island Jewish Medical Center, New Hyde Park, New York, and the State University of New York, Stonybrook, New York
A B S T R A C T This study of 2,549 urology patients examined resource consumptiort i:,¢ ro,,l~:e Of admission into the hospital. Almost all urologic admissions were more expens~:ve as e:,~erg~~.:~c~es. These more expensive emergency urologic admissions had higher diagnostic costs, a lo'nge~ h~,.!ip~~al length of stay, and a greater severity of illness than their less expensive non-emergency cr~z::~iIeq:~oft. The more expensive emergency admission had a high referral rate to urology from non.ur,:m,lo:!'ie clinical services. These findings suggest that efficiency might be improved in the emer~:enc~1 u-'ologic patients by increasing the speed of diagnosis and admission of patients to the aplproi,:,'id~te, clinical service (urology).
Payment changes underway for the reimbursement of hospitals and physicians will cause physicians to study methods to improve efficiency. Our group has been interested in route of admission (i.e., emergency vs nonemergeney) characteristics for groups of hospitalized patients. Two findings seem applicable from a number of our studies eoneerning the Medicare Diagnostic Related Group (DRG) prospective hospital payment system, i.e., emergency admissions may tend to generate financial risk under DRG, and emergency admissions are usually more costly per DRG than their nonemergency counterpart. 2'a The purpose of this study was to more precisely quantify resource consumption for urology patients by route of admission into the hospital. Important parameters measured were total hospital costs, hospital length of stay, diagnostic costs, severity of illness, and change in clinical service, i.e., referral to urology service from another elinical service.
548
Material and Methods
Study design We determined which DRGs had 15or :more patients admitted through the emergency room (ER) and 5 or more patients not admitted through the ER, and at least 1,0 19e:~cent or more of the total DRG population admitted through the ER. Patients in those DRCs whicl~ fit the aforementioned criteria were inchltde~3in the study (N = 2,549). The DRGs were div:ided into two groups. Costs for patients wIao were admitted through the ER were higher than for those who were not admitted through the ER (ER > non-ER), and DRG costs for patients who were admitted through the ER were tess than for patients who were net admRted through the ER (non-ER > ER). Analytic comparisons All adult urology patients fitting the study design during 1985 and 1986 were analyzed. UROLOGY
/
JUNE i990
VOLUME XXXV, NUMBEtR 0
TABLE I.
Besource characteristics (mean~patient): EB > non-ER and non-EB > EB
--ER > Non-ER EI1 Non-ER 361 1,911 1.1535" 1.2344 12.0~ 7.4 $9,122~ $6,410 $1,69511 $1,178 6.1% II 1.6 % ($1,456) ~ $1,465 2.66~ 2.14 2.93 2.78 5.59 4.93 1.4 % 1.2 %
Characteristic Sample size DItG wt. index (mean) Hosp. length (days) Total costs Diagn. costs Outliers DRG profit/ (loss) No. of diagn.¶ No. of procedures~[ Total severity~[ Mortality
Non-ER > El( ER Non-ER 147 i31 0.7326 0.7426 4.65 6.5 $3,604§ $5,286 $7665 $1,005 0.7 % 1.5 % $1,680§ $66 1.98 "2.12 1.03§ 1.97 3.02 4.09 0.7 % 0%
*Star. diff. at p < 0.03 from non-ER category. tStat, diff. at p < 0.0001 from non-ER category. ~:Stat. diff. at p < 0.05 from non-Ell category. §Star, diff. at p < 0.002 from non-Ell category. IlProfit/loss under DtlGs: parentheses = loss. ~Number of ICD-9-CM eodes/patient.
Our hospital costing methodology is a stepdown alloeative method contained on our Medicare cost report and outlined in other works. 4 Diagnostic costs were computed as a total of laboratory costs (urinalysis, hematology, coagulation, biochemistry, and microbiology) and diagnostic radiology costs. The total number of ICD-9-CM (International Classification of Diseases [9th Rev.] Clinical Modification) diagnoses and procedure codes per patient at discharge were used as a proxy for severity of illness. A change in service was described as admission to other than the discharging service, i.e., urology. A number of parameters were analyzed per patient for both ER and non-ER groups including: total hospital cost, hospital cost by hospital service (room and board, laboratory, radiology, blood, operating room-recovery room, central supply-pharmacy, and other), the mean DRG weight index, the hospital length of stay (LOS) in days, percent outliers, profit or loss under D R G r e i m b u r s e m e n t , n u m b e r of ICD-9diagnoses codes, number of ICD-9-CM procedure codes, and mortality. Data were computed as a mean per patient _+ standard deviation. Student's t test was used to test for statistical significance between groups of patients. Results The 2,272 admissions in the ER > non-ER category generated $15,542,284 in total hospital costs, $3,292,983 for the 361 ER admissions, and $12,249,300 for the 1,911 non-ER admissions. The 278 admissions in the non-ER > Etl
UROLOGY
/
JUNE 1990
/
VOLUME XXXV, NUMBER 8
I'V'~ L SO
lut-
"55.82_ i
2g
qq. 7
29.q ig
IIII I
:roT.az co$~'B
]
n~RCTY
MR OREalrERTH*N HOIC-ER
i
O g ZL£*VBB$
[]
DZaOHO~rrlC C0$cr5 lqt~H-NR
IIR~RTEIqTHOleI~R
FICURE 1.
Components of higher costs: for EB > non-EB diagnostic costs, total costs, and severity of illness were higher for EB admissions. Non-Etl > ER displayed same characteristics with total costs and severity more so, and diagnostic costs less so.
category generated $1,222,165 in total hospital costs: $529,751 for the 147 ER admissions, and $692,414 for the 131 non-ER admissions. For the entire 2,549 study population, 89.1 percent of patients were admitted in the DRG group and per patient ER costs were greater than nonER costs (10.9%). The higher costs of the ER > non-ER category were associated with a 36.7 percent greater total hospital cost, a 21.6 percent greater severity of illness, and a 53.8 percent greater diagnostic cost (all 3 corrected for DRG weight index) (Fig. 1). Aggregate characteristics of the Ell > non-ER category are shown in Table I. ER admissions had a 6.5 percent 549
f
smaller mean DllG weight index compared with non-Eli admissions, but they had a 42.3 percent greater total hospital cost per patient, a 66.2 percent greater hospital length of stay, and a 43.8 percent greater diagnostic cost. In addi~ tion, the percent outliers, the financial risk, the number of ICD-9-CM diagnoses and procedure codes, and the mortality were higher for Et{ compared with non-EB admissions. The greater the cost of the non-EI/ > Ell category was associated with a 44.7 percent greater total hospital cost, a 34.0 percent greater severity of illness, and a 29.4 percent greater diagnostic cost (all 3 corrected for DllG weight index) (Fig. 1). Aggregate characteristics of the non-Eli > Eli category are shown in TaMe Io Non-Ell admissions had a 1.4 percent greater DllG weight index than EB admissions; they had 44,7 percent greater total hospital cost per patient, a 40.1 percent greater hospital length of stay, and 31.2 percent greater diagnostic cost. Although non-ER admissions had higher resource utilization, greater financial risk, and a greater severity of illness than ER admissions in this category, the differences were less striking than in the ER > non-ER group. Change in clinical service was highest for Eli admissions in the EB > non-Ell category (18 of 361 patients), non-ER admissions in this category demonstrated that 3 0 o f 1,911 changed clinical service (p < 0.005) (Fig. 2). In the nonEll > Ell category, non-Ell admissions generated I of 131 patients with a change in clinical service, whereas for Ell admissions in this
group 4 of 147 changed clinical service (p = N.S.). Comment The purpose of this study was to analyze hospital resource consumption for urology patients by route of admission into the hospital. Almost all emergency urology admissions were more costly than nonemergeney admissions. Emer, gency urologic admissions had higher diagnostic costs, a longer hospital stay, and a greater severity of illness than their less expensive nonemergency counterparts. The small group of patients where nonemergeney admissions were more costly than emergency admissions demonstrated these same trends. These findings may offer opportunities to improve efficiency for urology patients. Our data suggest that total hospital costs might be reduced for the more expensive emergency urologic patient by increasing tile speed of diagnosis, possibly by examining the sequence and timing of preoperative testing for these patients. One study by our group of emergency surgical admissions undergoing eholecystectomy suggested that the diagnostic costs for these patients were much higher than those for nonemergency surgical patients undergoing choiecystectomy. 5 This current study defines these higher diagnostic costs more precisely. In another study by our group we examined the preoperative length of stay for emergency surgical patients undergoing other common general surgical procedures. Emergency general surgical admissions tended to have relatively long preoperative lengths of stay. 6 This study suggested that total costs might be reduced in ~his population by increasing the speed of diagnostic testing and facilitating operative scheduling to avoid delays. It is possible that efficiency may be improved for the emergency urologic admission, but further study will be needed along these lines. The change in clinical service findings of this study may be important for both cost containment and quality assurance. The more expensive emergency urologic admission had the greatest rate in change in clinical service (i.e,, referred to urology from another clinical service). One of our previous studies had suggested that a chang e in clinical service was associated with higher hospital costs. 7 We studied patients undergoing craniotomy (i.e., DBG 1) and found that patients referrec} to neurosurgery for craniotomy had much higher costs than nonreferred patients. Many of these more expensive
550
UROLOGY
~T
°E ]
!
,I, HR OR~TE~'THnHXOH-ER
L'RP,eT2"/~'M~.5"
HOCl-.ER OR1E,ffTBR THOle ~EI~
]
lgOH-2~RP,~TI,EJq"f$
FIaURE 2. Change in clinical service was greatest for emergency admission in the EB > non-EB category.
/ JUNE 1990
/
VOLUME XXXVo NUMBEI~ 6
referred craniotomy patients were admitted to the neurology service, then much later in their hospital stay referred to neurosurgery for eraniotomy. This craniotomy study did suggest that, if possible, admission to the appropriate clinical service might improve efficiency. Change in clinical service also may be of interest to those in the hospital sector focusing on quality assurance. We have studied a small group of patients referred to the general surgical service from the medical service, vis-a-vis their quality of care. 8 Referred patients were more likely to have deficiencies in quality of care than nonreferred patients. Thus referred patients were more likely to suffer errors in diagnosis and/or management, or delays in surgery, compared with nonreferred patients. It is possible that referred urologic patients may be more "vulnerable" to quality-of-care deficiencies. Further study will be needed along these lines. This study demonstrated that route of admission into the hospital may provide similar cost characteristics between groups of patients. It is possible that the study of these characteristics may offer opportunities to improve efficiency. Long after the era of hospital prospective DRG payment has ended, route of admission should offer opportunities to improve efficiency. The urologist will need to meet the challenge of the future, i.e., meeting "unlimited" demands with "limited" resources.
UROLOGY / JUNE 1990 /
VOLUMEXXXV, NUMBER 6
Department of Surgery Long Island Jewish Medical Center New Hyde Park, New York 11042
(DR, MUNOZ) ACKNOWLEDGMENT:To James Moyer, Seth Warren, and Gordan Doletto of the Divisions of Management Information Systems, and the DRC Task Force of the Long Island Jewish Medical Center, and Jonathan Coldstein for their data computation, and to Christina Weiss for assistance in the preparation of this manuscript.
References 1. Blendon RJ: Policy choices for the 1990s: an uncertain look into America's future, in Cinzberg E: The US Health Care System. A look to the 1990s, Totowa, N.J., Rowman & AUanheld, 1985. 2. Munoz E, et ah The financial effect of emergency room generated admissions under prospective payment systems, JAMA 254: 1763 (1985}. 3. Munoz E, Tinker MA, Margolis I, and Wise L: Surgonomics: the identifier concept. Hospital charges in general surgery and surgical subspecialfies, Ann Surg 202:119 (1985). 4. Munoz E, Margolis IB, and Wise L: Surgonomics: the cost demographics of choleeysteetomy, in Virgo J (Ed): Restructuring Health Policy: An International Challenge, Evansville, Ill., International Health Economies and Management Institute, 1986, pp 329-340. 5. Munoz E, Tinker MA, Margolis I, and Wise L: Surgonomics: the cost of cholecystectomy, Surgery 96:642 (1984). 6. Munoz E, et ah T h e identifier concept: clinical variables to manage costs for surgical patients, Hosp Health Serv Admin h 85 (1987). 7. Munoz E, et ah Surgenemics: the cost of craniotomy, Neurosurg 18" 321 (1986). 8. Munoz E, et ah The medical patient referred to general surgery, resource utilization and outcome under DRG reimbursement, Arn J Surg 157:237 (1989L
551
