HEALTH-CARE COST STUDIES
Awareness of the limits of health-care resources is increasing in medical circles, and studies on use of resources, often related to particular diseases, have proliferated in recent years. Most of these studies measure use in costs, expressed in the monetary unit of the country in question.
Cost studies can be based on incidence or prevalence , depending on the objectives of the study. Studies based on incidence have an unlimited time period (determined by the duration of the illness) and are useful when the results are to be used for making decisions on disease management. Studies based on prevalence, on the other hand, have a limited period (marked by the duration of the study) and are useful when the results are to be used for controlling costs.
There are several ways of classifying costs. To date, most data are organized into fixed costs and variable costs, fixed costs being those that remain the same irrespective of the disease under study (structural costs, staff salaries) and variable costs being those generated by the disease under study (diagnostic studies, treatment, time dedicated by health-care staff).
Another way of classifying costs divides them into direct, indirect, and intangible costs. Direct costs are those directly associated with the disease (eg, hospital admission, health-care attention, drugs), indirect costs are those associated with loss of productivity due to the disease (work days lost by the patient or the parent when the patient is a child, potential life years lost), and intangible costs are those that derive from the damage caused by the disease (loss of quality of life, psychological effects of being ill). Ideally, costs studies should include all three cost types, but this rarely occurs in practice due to the difficulty of expressing indirect and intangible costs in monetary units. There is little consensus, so most studies include only direct costs.
Studies can also be done from four different perspectives: that of the society, the patient, the health-care center, and the health-care system provider . Depending on the perspective, the various types of costs have more or less weight. For example, the social perspective is used for chronic diseases such as cancer, chronic obstructive pulmonary disease, diabetes, and AIDS, all of which use a large amount of resources, both health-care and other. On the other hand, health-care studies from the perspective of either the health-care center or the health service provider are usually performed for acute diseases such as community-acquired pneumonia (CAP).
In population-based studies, CAP-related costs are difficult to quantify. The disease is difficult to diagnose, and so true incidence is difficult to determine . Several factors complicate quantification. First, the diagnosis should be confirmed by radiographs, but this is not always available with primary care consultation, which leads to many patients being diagnosed and treated without radiographic confirmation. Second, no consensus has been reached over the length of time needed between hospital discharge and onset of CAP for the disease not to be considered nosocomial, with variations in the literature from 3 to 14 days. Third, there are no standard criteria for classifying patients who are in residential care, infected with AIDS, or have active cancer, so in some studies they are included in the same group, and in others, not. Fourth, diagnostic error of up to 21.5% has been described for CAP when these patients have been followed until outcome of the disease . This could lead to other pulmonary diseases being mistaken for CAP, unless the disease is followed through to outcome. Thus, apart from the natural variability of the disease, there is considerable variation in the reported incidence, even within the same country, which complicates estimation of costs.
Of the literature, the studies carried out in the United States between 1984 and 1995 are very interesting. The outpatient cost of CAP was calculated to be 8% of the total cost, and hospital costs made up the other 92% . The high hospital cost was mainly caused by length of stay [6,7] but also by the type of hospital. One study performed in Pennsylvania on patients older than 65 years found that costs for patients treated in university hospitals were 15% higher than costs for those treated in general hospitals. The difference was justified by the fact that specialist doctors used 11% more health-care resources than did general practitioners .
Other health-care costs, however, must be considered, such as visits to doctors at health-care centers, visits to doctors away from the hospital, and hospital emergency services. Complementary explorations (radiographs, laboratory tests, etc) and ambulance costs must also be included. Costs not related to health care, which are much more difficult to calculate , include travel costs met by the patient, waiting times, and investment in examinations and disease prevention.
Indirect costs include lost work days or the inability of the patient to perform normal activities, and, given that CAP is a potentially fatal disease, potential life years lost. As these factors are difficult to quantify, an estimation based on an average interprofessional salary is usually used. Intangible costs, although not as relevant because CAP is an acute disease, must be considered and include lost autonomy, especially relevant for the elderly.
Studies on the costs of CAP are usually carried out from the health-care-center perspective, so that the great differences in methodology make drawing comparisons between studies practically impossible.
RESOURCE UTILIZATION FOR CAP
A population-based study carried out in Spain showed that diagnostic yield at the primary care level was surprisingly low (20% of cases) despite the fact that it plays an important role in the management of CAP . Likewise, a study by Weingarten et al  found that 55% of CAP diagnoses were established in the emergency department. This may be due to patients being referred to the hospital emergency department in the absence of chest radiograph facilities in primary care and also the tendency of some patients to seek care directly at hospital emergency services . In the study of Bartolomé et al , 44% of patients visited both the outpatient clinics of hospitals and primary care centers following hospital discharge, and a resulting 96.6% of patients visited the practitioner at least once. It should be noted that 10% of patients attended at the hospital emergency service and referred for ambulatory care were given appointments to visit the same service, although the management of these patients could have been performed at a less costly level, such as primary care . A total of 500 visits attributable to CAP were made annually at the three levels of care—primary, hospital emergency department, and hospital outpatient clinic . The percentage of patients receiving inpatient care varies from 18 to 60% in population-based studies [9,11,12]. This may be explained by several factors, including easy access to hospitals  and availability of beds, age of the population, comorbidity, and subjective criteria in the decision to hospitalize. However, it has been shown that attending physicians tend toward admission rather than outpatient care if there is any doubt about outcome  and that the physician’s speciality also influences determination of the initial site of care .
Mean length of hospitalization ranges from 7 to 13 days in data reported in several studies [4,9,15-19]. Interhospital variations in length of stay can be attributed to three major characteristics: first, health-care systems and hospital management; second, physicians’ practices and skills; and third, patient characteristics.
In the multicenter study carried out by Cabré et al , hospitalizations with shorter length of stay were not associated with increased postdischarge mortality or readmission, but no consensus has been reached over the optimal length of stay for CAP patients. Readmissions range from 4 to 14% in the literature [10,19] and admission of patients initially treated as outpatients from 2.8 to 7.1% .
The mean duration of outpatient antibiotic treatment should be adjusted to the 8 to 10 days proposed for low-risk classes of CAP , but 14 days is reported in the literature . In several studies, intravenous antibiotic treatment lasted for 6 to 7 days [9,12,17,18]. However, 2 to 3 days of intravenous antibiotic therapy may be equally effective and would be associated with a decrease in length of stay and reduction of costs in low-risk patients [17,20].
In the literature, the time interval from clinical outcome to a return to normal daily activities varies from a range of 6 to 8 days [10,12] to a range of 22 to 25 [4,9] or even 40  days. Delay in returning to normal activities may be related to factors such as the persistence of some symptoms such as asthenia, especially in Chlamydophila pneumonia , waiting time for radiograph results, and patient age.
COSTS OF CAP
The marked differences between national health-care systems are an important limitation to the external validity of cost studies. However, valid inferences may be established for the percentages of costs associated with the different levels of care, particularly in many European countries where primary care is a first-line health-care facility, unlike in the United States and Canada. In Spain, Bartolomé et al  reported that, of 205 CAP patients treated in 1994/1995 in the public health-care system, 59.8% were treated as inpatients and accounted for 92% of the annual costs of CAP . A large study carried out by Guest and Morris  in 1992/1993, using data from the National Health Service in the United Kingdom, found that the 32% of all episodes of CAP treated in hospital accounted for 96% of the annual cost of this disease. Niederman et al  and Whittle et al  in the United States have reported that 95% and 81%, respectively, of the overall costs of treating pneumonia were associated with inpatient care. In the study of Birnbaum et al , carried out on employed persons, this percentage decreased to 63%.
Bartolomé et al  reported that the cost of treating a patient with CAP in a hospital was €1,553, later corroborated by other studies carried out in Spain . In other countries, costs vary according to the country and the methodology from $1,333 (in Germany) to $10,200 (in the United States) [26,27]. Between 55 and 77% of inpatient costs are due to lodging and staff costs.
Treatment represents between 10 and 15% of the costs of CAP (Figure 1) [9,16,25-29]. According to Reyes et al , 79% corresponds to the cost of the antibiotic, which varies according to the type of antibiotic used in relation to the gravity of the CAP and the possible complications that could arise. Bauer et al  reported that the use of more expensive antibiotics such as fluoroquinolone was associated with a reduction in length of stay and did not affect total cost. Other studies have shown that the use of a macrolide, a possibly cheaper alternative, was associated with increased mortality and cost through hospitalization from treatment failure [30,31], but studies on penicillin resistance do not show this increased cost . However, Nicolau et al  did find that pathogen resistance to antibiotics affected cost and recommended that treatment follow clinical practice guidelines. More studies are undoubtedly needed to assess the true influence that antibiotic therapy has on CAP costs.
| ||Figure 1. Distribution of total cost of community-acquired pneumonia. |
(Adapted with permission from Bartolomé M, Almirall J, Morera J, et al. A population-based study of the costs of care for community-acquired pneumonia. Eur Respir J 2004;23:610-616)
In the few studies on the cost of outpatient setting treatment, we found cost estimated between €196  and €493 , 79% of this cost being due to visits and 17 to 23% to treatment.
It is interesting to compare the difference between inpatient and outpatient treatment. Costs of inpatient treatment are 7.9 times higher than those of outpatient care in the population-based study of Bartolomé et al  in Spain (12.2 times higher than CAP treated exclusively in a primary care setting). These differences could be greater in countries including the United Kingdom, possibly reaching 17 to 50 times greater, depending on length of stay . In studies that were not population-based, the direct costs of inpatient care were 4.4 and 8.0 times higher than those of outpatient care . It must be remembered that patients initially treated as outpatients but later hospitalized due to failed therapy can present six times greater costs .
When patients were stratified by age, the cost of treating patients older than 65 years was significantly higher than that for patients younger than 65 years, but older age was not an independent predictor of costs in the logistic regression analysis . This could have been due to the effect of other variables such as severity of illness and comorbidity, as recently shown in a study by Reyes et al  on the determinants of hospital costs in CAP. They found that complications, hypoalbuminemia, and previous hospital admission were the most important determinants of high costs associated with hospitalized CAP patients. However, neither patient age nor comorbidities contributed to increasing the direct costs.
Conversely, the percentage of cases of CAP not diagnosed at the initial visit suggests that primary care physicians are reluctant to order chest radiographs in febrile episodes. There are conflicting views over the necessity of performing radiographic studies in the primary care setting. In Europe, there is a trend toward treating pneumonia without radiographic confirmation because it is considered that, given the low cost of ambulatory treatment, a 25% diagnostic error would represent a 1% variation in cost . However, if more radiographic studies were performed in the primary care setting, the diagnostic yield would increase, which, in turn, would contribute to reducing the number of consultations at hospital emergency services and the possibility of inappropriate admissions to hospitals. Moreover, radiographic confirmation of the pneumonic infiltrate is important, given that previous respiratory infection is a risk factor for CAP . It is important to extend the radiographic follow-up of patients until outcome in order to prevent the inclusion of false negative cases, which could result in up to 18% additional cost .
Variability of direct costs is explained principally by length of stay , and there is general agreement that a substantial number of hospitalized patients with CAP could be treated as outpatients . Data from different studies indicate that 14.26 to 36% of hospital admissions could be avoided, with a reduction of 88.6 to 92.0% in the total costs of CAP attributable to hospitalization [9,36].
In order to reduce the number of patients hospitalized and length of stay, most cost-containment efforts have recommended the application of clinical guidelines [4,10]. Current clinical guidelines recommend using the Pneumonia Severity Index (PSI) developed by Fine  to stratify patients into risk classes on admission. The index is a useful prediction rule to improve appropriate hospitalization and prescribe the most cost-effective antibiotic treatment. Goss et al  showed that, using the PSI, only 8% of CAP included in PSI risk class I and II of their study could have been treated as outpatients. Atlas et al  also did a study on CAP patients in 1998, classifying them into PSI risk classes and applying an outpatient treatment model that included free medication and clinical follow-up. With this procedure they managed to reduce hospital admissions from 58 to 43% with respect to the control group.
More recently, a multicenter, randomized study in Canada included the PSI in clinical guidelines for CAP patient management in the hospital emergency department. The study showed that hospital admissions of low-risk patients (risk classes I-III) decreased by 18% (31% instead of 49%) .
Nevertheless, in some cases of low-risk PSI scores, hospitalization can be justified as demonstrated by Marras et al . In their study, 224 hospitalized CAP patients with low-risk PSI scores (I-III) were analyzed retrospectively to assess the usefulness of the scale in making the decision to hospitalize. Clinical records of all the patients were examined, and in 94% a justification for hospitalization was found. Of these, 52% had associated medical complications, 27% lived in precarious social conditions, 24% were considered failed therapy cases after outpatient antibiotic treatment, 19% needed oxygen therapy, and 3% were intolerant of oral medication. These results showed that low-risk patients are frequently hospitalized for concomitant factors not evaluated by the PSI.
For CAP patients who need hospitalization, another aspect for discussion is length of stay, which can depend on several factors, an important one being appropriate antibiotic therapy. Several authors have described how initial appropriate antibiotic selection is associated with shorter length of stay and how following clinical guidelines for antibiotic use reduces mortality and the readmission rate [29,41,42].
Baker et al  analyzed trends of mortality and readmission rates of Medicare patients discharged alive after hospitalization for various diseases, including pneumonia from 1991 to 1997. The mean length of stay decreased from 10.3 days in 1991 to 7.3 days in 1997, and their findings suggest that it is possible to reduce length of stay without jeopardizing patients’ health. These observations are supported by recent findings by Capelastegui et al  that the mean length of stay for patients aged 65 years or more decreased from 5.6 days in 2000 and 2001 to 3.7 days in 2006 and 2007. Fishbane et al  also managed a substantial reduction in length of stay while maintaining and improving quality of care for their patients.
It should be noted that 22% of patients could have been discharged from the hospital during the first 3 days following admission and that short hospital stays followed by care at other levels (primary care, home-care services, hospital outpatient clinics, skilled nursing facilities) should definitely be considered . It has been shown that 32% of costs are consumed during the first 2 days of hospitalization and that costs decrease thereafter . Bartolomé et al  reported an estimated 242 avoidable hospital days, a figure lower than might be expected considering the high percentage of inpatient care in their study.
Reduction in the utilization of resources should also be assessed from the point of view of marginal costs. Thus, shorter hospital stays may be associated with an increase in the number of readmissions and an increase in the number of patients initially treated in the primary care setting who require admission to the hospital, so the percentage of cost reduction (estimated at 17.4% by Bartolomé et al ) may vary substantially.
In summary, there are different ways to reduce CAP costs. First, reduce the incidence by prophylaxis (pneumococcal and influenza vaccines) . Second, reduce the percentage of hospitalization by increasing adherence to clinical guidelines . More frequent application of guidelines could contribute to shorter mean lengths of stay without putting patients at risk, and specialized home care could also be introduced [45,46]. Third, reduce length of stay [15,16,26,37] with early management, early change to oral antibiotics, and prevention of complications during hospitalization . Fourth, be aware of antibiotic resistance [26,30-33]. Fifth, investigate use of new antibiotics that do not induce resistance . Sixth, increase the use of primary care for follow-up visits and facilitate diagnosis at the primary care level .
In conclusion, CAP has a considerable economic impact on resource utilization related to a high percentage of inpatient care, long duration of antibiotic therapy, and a considerable number of visits at several health-care levels.
1. Rice DP. Cost-of-illness studies: fact or fiction? Lancet 1994;344:1519-1520. [Medline]
2. Mellis CM, Peat JK, Woolcock AJ. The cost of asthma: can it be reduced? Pharmacoeconomics 1993;3:205-219. [Medline]
3. Marrie TJ, Lau CY, Wheeler SL, et al. A controlled trial of a critical pathway for treatment of community-acquired pneumonia. Community-Acquired Pneumonia Intervention Trial Assessing Levofloxacin. JAMA 2000;283:749–755. [Medline]
4. McCormick D, Fine MJ, Coley CM, et al. Variation in length of hospital stay in patients with community-acquired pneumonia: Are shorter stays associated with worse medical outcomes? Am J Med 1999;107:5-12. [Medline]
5. Macfarlane J. An overview of community-acquired pneumonia with lessons learned from the British Thoracic Society study. Semin Respir Infect 1994;9:153-165. [Medline]
6. Almirall J, Bolibar I, Vidal J, et al. Epidemiology of community-acquired pneumonia in adults: a population-based study. Eur Respir J 2000;15:757-763. [Medline]
7. Lave JR, Lin CJ, Fine MJ, et al. The cost of treating patients with community-acquired pneumonia. Semin Respir Crit Care Med 1999;20(3):189-197. [Abstract]
8. Whittle J, Lin CJ, Lave JR, et al. Relationship of provider characteristics to outcomes, process, and costs of care for community-acquired pneumonia. Med Care 1998;36:977-987. [Medline]
9. Bartolomé M, Almirall J, Morera J, et al. A population-based study of the costs of care for community-acquired pneumonia. Eur Respir J 2004;23:610-616. [Medline]
10. Weingarten SR, Riedinger MS, Hobson P, et al. Evaluation of a pneumonia practice guideline in an interventional trial. Am J Respir Crit Care Med 1996;153:1110–1115. [Medline]
11. Bolibar I, Balanzó X, Armada A, et al. [Impact of the primary health care reform on the use of the hospital emergency services]. Med Clin (Barc) 1996;107:289-295. [Medline]
12. Gleason PP, Kapoor WN, Stone RA, et al. Medical outcomes and antimicrobial costs with the use of the American Thoracic Society guidelines for outpatients with community-acquired pneumonia. JAMA 1997;278:32–39. [Medline]
13. Porath A, Schlaeffer F, Lieberman D, et al. Appropriateness of hospitalization of patients with community-acquired pneumonia. Ann Emerg Med 1996;27:176–183. [Medline]
14. Jokinen C, Heiskanen L, Juvonen H, et al. Incidence of community-acquired pneumonia in the population of four municipalities in eastern Finland. Am J Epidemiol 1993;137:977–988. [Medline]
15. Cabré M, Bolivar I, Pera G, et al. Factors influencing length of hospital stay in community-acquired pneumonia: a study in 27 community hospitals. Epidemiol Infect 2004;132:821-829. [Medline]
16. Fine MJ, Pratt HM, Obrosky DS, et al. Relation between length of hospital stay and costs of care for patients with community-acquired pneumonia. Am J Med 2000;109:378-385. [Medline]
17. Siegel RE, Halpern NA, Almenoff PL, et al. A prospective randomized study of inpatient IV antibiotics for community-acquired pneumonia. The optimal duration of therapy. Chest 1996;110:965–971. [Medline]
18. Gilbert K, Gleason PP, Singer DE, et al. Variations in antimicrobial use and cost in more than 2,000 patients with community-acquired pneumonia. Am J Med 1998;104:17–27. [Medline]
19. Frias J, Gomis M, Prieto J, et al. Initial empirical antibiotic treatment of community-acquired pneumonia. Rev Esp Quimioter 1998;11:255-261. [Medline]
20. Cunha BA. Community-acquired pneumonia. Cost-effective antimicrobial therapy. Postgrad Med 1996;99:109-123. [Medline]
21. Marrie TJ, Peeling RW, Fine MJ, et al. Ambulatory patients with community-acquired pneumonia: the frequency of atypical agents and clinical course. Am J Med 1996;101:508-515. [Medline]
22. Guest JF, Morris A. Community-acquired pneumonia: the annual cost to the National Health Service in the UK. Eur Respir J 1997;10:1530-1534. [Medline]
23. Niederman MS, McCombs JS, Unger AN, et al. The cost of treating community-acquired pneumonia. Clin Ther 1998;20:820-837. [Medline]
24. Birnbaum HG, Morley M, Greenberg PE, et al. Economic burden of pneumonia in an employed population. Arch Intern Med 2001;161:2725-2731. [Medline]
25. Reyes S, Martinez R, Vallés JM, et al. Determinants of hospital costs in community-acquired pneumonia. Eur Respir J 2008;31:1061-1067. [Medline]
26. Bauer TT, Welte T, Ernen C, et al. Cost analyses of community-acquired pneumonia from the hospital perspective. Chest 2005;128:2238-2246. [Medline]
27. Colice GL, Morley MA, Asche C, et al. Treatment costs of community-acquired pneumonia in an employed population. Chest 2004;125:2140-2145. [Medline]
28. Sun HK, Nicolau DP, Kuti JL, et al. Resource utilization of adults admitted to a large urban hospital with community-acquired pneumonia caused by Streptococcus pneumoniae. Chest 2006;130:807-814. [Medline]
29. Menéndez R, Reyes S, Martínez R, et al. Economic evaluation of adherence to treatment guidelines in nonintensive care pneumonia. Eur Respir J 2007;29:751-756. [Medline]
30. Paladino JA, Adelman MH, Schentag JJ, et al. Direct costs in patients hospitalised with community-acquired pneumonia after non-response to outpatient treatment with macrolide antibacterials in the US. Pharmacoeconomics 2007;25(8):677-683. [Medline]
31. Asche C, McAdam-Marx C, Seal B, et al. Treatment costs associated with community-acquired pneumonia by community level of antimicrobial resistance. J Antimicrob Chemother 2008;61(5):1162-1168. [Medline]
32. Nicolau D. Clinical and economic implications of antimicrobial resistance for the management of community-acquired respiratory tract infections. J Antimicrob Chemother 2002;50(suppl 1):S61-S70. [Medline]
33. Monte SV, Paolini NM, Slazak EM, et al. Costs of treating lower respiratory tract infections. Am J Manag Care 2008;14(4):190-196. [Medline]
34. Almirall J, Bolíbar I, Balanzo X, Gonzáles CA. Risk factors for community-acquired pneumonia in adults: a population-based case-control study. Eur Respir J 1999;13:349–355. [Medline]
35. Cots Reguant F, Castells Oliveres X, Garcia Altes A, et al. Relación de los costes directos de hospitalización con la duración de la estancia. Gac Sanit 1997;11:287-295. [Medline]
36. Fine MJ, Auble TE, Yealy DM, et al. A prediction rule to identify low-risk patients with community-acquired pneumonia. N Engl J Med 1997;336:243-250. [Medline]
37. Goss CH, Rubenfeld GD, Park DR, Sherbin VL, Goodman MS, Root RK. Cost and incidence of social comorbidities in low-risk patients with community-acquired pneumonia admitted to a public hospital. Chest 2003;124(6):2148-2155. [Medline]
38. Atlas S, Benzer T, Borowsky L, et al. Safely increasing the proportion of patients with community-acquired pneumonia treated as outpatients. Arch Intern Med 1998;158:1350-1356. [Medline]
39. Marrie TJ, Lau CY, Wheeler S, et al. A controlled trial of a critical pathway for treatment of community-acquired pneumonia: link between quality of care and ressource utilization. JAMA 2000;283:749-755. [Medline]
40. Marras TK, Gutierrez C, Chan CK, et al. Applying a prediction rule to identify low-risk patients with community-acquired pneumonia. Chest 2000;118:1339-1343. [Medline]
41. Capelastegui A, España P, Quintana JM, et al. Declining length of hospital stay for pneumonia and postdischarge outcomes. Am J Med 2008;121:845-852. [Medline]
42. Battleman DS, Callahan M, Thaler HT. Rapid antibiotic delivery and appropriate antibiotic selection reduce length of hospital stay of patients with community-acquired pneumonia. Arch Intern Med 2002;162:682-688. [Medline]
43. Baker DW, Einstadter D, Husak SS, et al. Trends in post-discharge mortality and readmissions: Has length of stay declined too far? Arch Intern Med 2004;164:538-544. [Medline]
44. Fishbane S, Niederman MS, Daly C, et al. The impact of standardized order sets and intensive clinical case management on outcomes in community-acquired pneumonia. Arch Intern Med 2007;167:1664-1669. [Medline]
45. Yealy DM, Auble TE, Stone RA, et al. Effect of increasing the intensity of implementing pneumonia guidelines: a randomized, controlled trial. Ann Intern Med 2005;143:881-894. [Medline]
46. Capelastegui A, España PP, Quintana JM, et al. Improvement of process-of-care and outcomes alter implementing a guideline for management of community-acquired pneumonia: a controlled before-and-after study. Clin Infect Dis 2004;39:955-963. [Medline]