International Journal of Technology Assessment In Health Care, 8:Suppl. 1 (1992), 49-56. Copyright © 1992 Cambridge University Press. Printed in the U.S.A.
PROBLEMS AND PROSPECTS IN THE ECONOMIC EVALUATION OF ANTENATAL CARE Harald Buhaug Norwegian Institute for Hospital Research, Trondheim
Abstract Economic evaluations can be used to compare alternative antenatal care programs in terms of cost and outcome. The cost of routine antenatal care is small compared to the total cost associated with pregnancy and childbirth. The main problem in economic evaluations is related to outcome measurement.
THE BASIC ELEMENTS OF AN ECONOMIC EVALUATION Overview
Economic evaluation has been defined as the comparative analysis of alternative courses of action in terms of both their costs and consequences (2). The basic logic of an economic evaluation in antental care is shown in Figure 1. The antenatal care program commands the use of health care resources, partly to carry out routine activities and partly to initiate other diagnostic or therapeutic activities, for instance by referring patients to a hospital outpatient clinic. Some of the activities depend on the health status of the patient, which itself is affected by the program. In an economic evaluation, we need to identify the areas of resource use influenced by the program, to measure the amount of use, and finally to compute the cost by valuing the resource use in monetary terms. Not only health care costs, but all use of resources incurred by the program should be included, for instance, the use of patients' time, traveling cost, and out-of-pocket expenses for patient or family. Some decision makers might be interested only in costs affecting their own budgets. In this case, we get an evaluation from that decision maker's point of view, which might be useful to him or her, but may also be very different from an overall societal evaluation. Health status affects the productive capacity of the patient. In practice, sick leave is commonly used as an indicator for loss of productive output. The associated cost is the value of this loss, and not the compensation paid by social security. The loss of productive output is added to the rest of the cost components. Health outcome is discussed later. At this point, we should note only that health outcome of pregnancy affects the future lives of mother and child. In an economic evaluation, future life years and future quality of life should be taken into account, as well as future use of health care and other services, and future productive output. Economic evaluations deal with alternative courses of action. Two types of alter49
Buhaug Antenatal care Health status
Resource use Productive output
Health outcome
Net cost
Comparision Figure 1. Economic evaluation in antenatal care.
natives to a given program exist: do nothing or introduce a different program. If we ask whether routine antenatal care is worthwhile, doing nothing is the alternative we will have to consider. It is hard to tell exactly what would happen if no routine care were offered. Most likely, unorganized antenatal care would flourish. We should also consider the loss of possible placebo or Hawthorn effects of routine care, such as general motivation and emotional support. In this article, only the evaluation of one routine program against another is considered. In comparing program alternatives, our interest is the differences between the alternatives rather than absolute figures. If we compare a suggested alternative to an existing program, it is possible that the net cost of that alternative is negative, which means that it is less costly. Savings can be due to less direct program cost, but also to reductions in unnecessary referrals, prevented morbidity, and other factors. The final step in the evaluation is the comparison of net cost with health outcome, or rather the difference in net cost with the difference in health outcome. Alternative A is preferable to alternative B in the following situations: 1. Alternative A is less costly, and the health outcome of A is equal to or better than that of B. 2. Alternative A is equal to B in terms of cost, and the health outcome of A is better than that of B. 3. Alternative A is more costly and renders a better health outcome than alternative B, and the extra cost is justified by the improvement in outcome. 4. Alternative A is less costly and also inferior in terms of health outcome, and the loss in terms of health outcome is justified by the savings. In cases 1 and 2, it is necessary only to rank the alternatives in terms of cost and health outcome. If we are sure of the ranking order, more exact calculations are not required. In cases 3 and 4, we need to balance a difference in cost against a difference in outcome. This might call for more exact calculations, and a valuation of health outcome in monetary terms is implied.
50
INTL. J. OF TECHNOLOGY ASSESSMENT IN HEALTH CARE 8:SUPPL. 1, 1992
Basic elements of an economic evaluation Table 1 . Child Outcome Measurement: Probability of Outcome, Discounted Future QALYs, and Cost and Productive Output Outcome Spontaneous abortion Induced abortion Perinatal death Major injury/disability Minor injury/disability Healthy
Probability
QALYs
Cost and output
pi p2 p3 pt ps p6
0 0 0 Qt Qs Q6
0 0 0 C« Cs C6
Expected no. of QALYs = I PiQr, expected future cost = I P,C,.
Health Outcome and Effectiveness
Perinatal mortality is probably the most frequently used indicator of outcome of pregnancy. As an indicator of outcome, perinatal mortality might be misleading, because it is defined in terms only of those who completed their pregnancies. A decrease in perinatal mortality does not necessarily imply that more babies survive. The reason for such a decrease might be that a higher fraction of high-risk pregnant women had an abortion. This is illustrated by a recent study that indicates that abortions are one of the most cost-effective ways to reduce perinatal mortality (5). To avoid ambiguities, outcome should be defined in terms of a more complete classification, for instance, live, healthy; live, minor injury/disability/risk; live, major injury/disability/risk; perinatal death; induced abortion; and spontaneous abortion. Birthweight is frequently used as an indicator of health outcome. If desired, we can replace "live, healthy" with "live, birthweight 3*2,500 g," and the categories minor and major health problems by birthweight 1,500-2,499 g and
PROBLEMS AND PROSPECTS IN THE ECONOMIC EVALUATION OF ANTENATAL CARE Harald Buhaug Norwegian Institute for Hospital Research, Trondheim
Abstract Economic evaluations can be used to compare alternative antenatal care programs in terms of cost and outcome. The cost of routine antenatal care is small compared to the total cost associated with pregnancy and childbirth. The main problem in economic evaluations is related to outcome measurement.
THE BASIC ELEMENTS OF AN ECONOMIC EVALUATION Overview
Economic evaluation has been defined as the comparative analysis of alternative courses of action in terms of both their costs and consequences (2). The basic logic of an economic evaluation in antental care is shown in Figure 1. The antenatal care program commands the use of health care resources, partly to carry out routine activities and partly to initiate other diagnostic or therapeutic activities, for instance by referring patients to a hospital outpatient clinic. Some of the activities depend on the health status of the patient, which itself is affected by the program. In an economic evaluation, we need to identify the areas of resource use influenced by the program, to measure the amount of use, and finally to compute the cost by valuing the resource use in monetary terms. Not only health care costs, but all use of resources incurred by the program should be included, for instance, the use of patients' time, traveling cost, and out-of-pocket expenses for patient or family. Some decision makers might be interested only in costs affecting their own budgets. In this case, we get an evaluation from that decision maker's point of view, which might be useful to him or her, but may also be very different from an overall societal evaluation. Health status affects the productive capacity of the patient. In practice, sick leave is commonly used as an indicator for loss of productive output. The associated cost is the value of this loss, and not the compensation paid by social security. The loss of productive output is added to the rest of the cost components. Health outcome is discussed later. At this point, we should note only that health outcome of pregnancy affects the future lives of mother and child. In an economic evaluation, future life years and future quality of life should be taken into account, as well as future use of health care and other services, and future productive output. Economic evaluations deal with alternative courses of action. Two types of alter49
Buhaug Antenatal care Health status
Resource use Productive output
Health outcome
Net cost
Comparision Figure 1. Economic evaluation in antenatal care.
natives to a given program exist: do nothing or introduce a different program. If we ask whether routine antenatal care is worthwhile, doing nothing is the alternative we will have to consider. It is hard to tell exactly what would happen if no routine care were offered. Most likely, unorganized antenatal care would flourish. We should also consider the loss of possible placebo or Hawthorn effects of routine care, such as general motivation and emotional support. In this article, only the evaluation of one routine program against another is considered. In comparing program alternatives, our interest is the differences between the alternatives rather than absolute figures. If we compare a suggested alternative to an existing program, it is possible that the net cost of that alternative is negative, which means that it is less costly. Savings can be due to less direct program cost, but also to reductions in unnecessary referrals, prevented morbidity, and other factors. The final step in the evaluation is the comparison of net cost with health outcome, or rather the difference in net cost with the difference in health outcome. Alternative A is preferable to alternative B in the following situations: 1. Alternative A is less costly, and the health outcome of A is equal to or better than that of B. 2. Alternative A is equal to B in terms of cost, and the health outcome of A is better than that of B. 3. Alternative A is more costly and renders a better health outcome than alternative B, and the extra cost is justified by the improvement in outcome. 4. Alternative A is less costly and also inferior in terms of health outcome, and the loss in terms of health outcome is justified by the savings. In cases 1 and 2, it is necessary only to rank the alternatives in terms of cost and health outcome. If we are sure of the ranking order, more exact calculations are not required. In cases 3 and 4, we need to balance a difference in cost against a difference in outcome. This might call for more exact calculations, and a valuation of health outcome in monetary terms is implied.
50
INTL. J. OF TECHNOLOGY ASSESSMENT IN HEALTH CARE 8:SUPPL. 1, 1992
Basic elements of an economic evaluation Table 1 . Child Outcome Measurement: Probability of Outcome, Discounted Future QALYs, and Cost and Productive Output Outcome Spontaneous abortion Induced abortion Perinatal death Major injury/disability Minor injury/disability Healthy
Probability
QALYs
Cost and output
pi p2 p3 pt ps p6
0 0 0 Qt Qs Q6
0 0 0 C« Cs C6
Expected no. of QALYs = I PiQr, expected future cost = I P,C,.
Health Outcome and Effectiveness
Perinatal mortality is probably the most frequently used indicator of outcome of pregnancy. As an indicator of outcome, perinatal mortality might be misleading, because it is defined in terms only of those who completed their pregnancies. A decrease in perinatal mortality does not necessarily imply that more babies survive. The reason for such a decrease might be that a higher fraction of high-risk pregnant women had an abortion. This is illustrated by a recent study that indicates that abortions are one of the most cost-effective ways to reduce perinatal mortality (5). To avoid ambiguities, outcome should be defined in terms of a more complete classification, for instance, live, healthy; live, minor injury/disability/risk; live, major injury/disability/risk; perinatal death; induced abortion; and spontaneous abortion. Birthweight is frequently used as an indicator of health outcome. If desired, we can replace "live, healthy" with "live, birthweight 3*2,500 g," and the categories minor and major health problems by birthweight 1,500-2,499 g and
