Economic burden of hospital admissions for patients with acute bacterial skin and skin structure infections in the United States

ABSTRACT

Objectives: We estimated the total US hospital costs associated with acute bacterial skin and skin structure infection (ABSSSI) admissions as well as the admissions that may have been potential candidates for outpatient parenteral antimicrobial therapy (OPAT).

Methods: We assessed inpatient admissions for ABSSSI from the Premier database (2011–2014), focusing on all admissions of adults with length of stay (LOS) ≥ 1 days and a primary diagnosis of erysipelas, cellulitis/abscess, or wound infection. We performed a detailed analysis of 2014 admissions for patient, treatment, hospital, and economic characteristic variables. Using published selection criteria, we identified a subset of patients admitted in 2014 who may have been potential candidates for OPAT.

Results: We analyzed 277,971 admissions. In 2014, most admissions were for cellulitis without major complications or comorbidities; mean ± SD LOS was 4.0 ± 3.0 days, and total hospital cost per admission was $6400 ± $6874, 54% of which was attributable to room costs. Among 2014 admissions, 14% involved patients with clinical characteristics suggesting that they were consistent with guideline recommendations for exclusive treatment with OPAT. Compared with all admissions in the year, these admissions were of younger patients (aged 50 vs. 55 years), admitted more frequently for cellulitis (90% vs. 70%), with shorter LOS (2.8 ± 1.8 days), and lower mean total hospital cost per admission ($4080 ± $3066).

Conclusions: Admissions for ABSSSI impose a substantial cost to US hospitals, with half of costs attributable to room costs. When extrapolated to all US patients admitted to the hospital for ABSSSI during 2014, had OPAT guidelines been universally followed, admissions may have been reduced by 14%, thereby saving US hospitals $161 million.     

The economic impact of methicillin-resistant Staphylococcus aureus in Canadian hospitals.

OBJECTIVES: To determine the costs associated with the management of hospitalized patients with methicillin-resistant Staphylococcus aureus (MRSA), and to estimate the economic burden associated with MRSA in Canadian hospitals. DESIGN: Patient-specific costs were used to determine the attributable cost of MRSA associated with excess hospitalization and concurrent treatment. Excess hospitalization for infected patients was identified using the Appropriateness Evaluation Protocol, a criterion-based chart review process to determine the need for each day of hospitalization. Concurrent treatment costs were identified through chart review for days in isolation, antimicrobial therapy, and MRSA screening tests. The economic burden to Canadian hospitals was estimated based on 3,167,521 hospital discharges for 1996 and 1997 and an incidence of 4.12 MRSA cases per 1,000 admissions. SETtING: A tertiary-care, university-affiliated teaching hospital in Toronto, Ontario, Canada. PATIENTS: Inpatients with at least one culture yielding MRSA between April 1996 and March 1998. RESULTS: A total of 20 patients with MRSA infections and 79 colonized patients (with 94 admissions) were identified. This represented a rate of 2.9 MRSA cases per 1,000 admissions. The mean number of additional hospital days attributable to MRSA infection was 14, with 11 admissions having at least 1 attributable day. The total attributable cost to treat MRSA infections was $287,200, or $14,360 per patient The cost for isolation and management of colonized patients was $128,095, or $1,363 per admission. Costs for MRSA screening in the hospital were $109,813. Assuming an infection rate of 10% to 20%, we determined the costs associated with MRSA in Canadian hospitals to be $42 million to $59 million annually. CONCLUSIONS: These results indicate that there is a substantial economic burden associated with MRSA in Canadian hospitals. These costs will continue to rise if the incidence of MRSA increases further.     

Estimating the cost of hospital treatment for injuries using linked morbidity data

This paper describes the analysis of injury-related linked hospital morbidity data by admissions and by individual patients in Western Australia (WA) from 1990 to 1994. Over this five-year period, there were an average of 35,385 admissions and 30,524 people admitted each year for injuries in WA. The age-standardised rates for injury-related hospital admissions and persons admitted for injuries increased significantly, by 2.4% and 1.5% per year respectively, over the five-year period. The number of admissions and the number of persons admitted peaked in the 20–24 years age group but the highest rates were among those aged 75 years and above.
Injuries accounted for nearly 10% of all hospital bed day costs and cost about $50 per head of population per year. The cost of hospitalisation rose steadily from $85.2 million in 1990 to $113.6 million in 1994, the average cost being nearly $100 million per year. The average cost per injury related hospital episode was $2,748.
Generally, the cost per hospital episode was higher for males and increased with age, following a similar pattern to that for the average length of stay.     

PMH2 Assessment of Health-Related Quality of Life During Treatment of Opiate Dependence using the Short Form-36

In the U.S., acute general hospitals increasingly provide treatment for patients with schizophrenia.
OBJECTIVE: To estimate the average annual cost of inpatient schizophrenia care per patient in an acute general hospital setting.
METHODS: Using ICD9 codes to identify disease and procedure-level data in five state (CA, FL, MA, MD, NC) acute care, all payer, discharge databases, an average cost per admission was estimated and combined with the frequency of admission calculated from the MA database to derive a mean annual acute care inpatient cost. Physician costs were calculated by applying 1997 Medicare fees to a resource use profile derived from the databases and published treatment recommendations. All costs are reported in 1997 US$, appropriately adjusted for medical inflation and cost-to-charge ratios.
RESULTS: Of 7.5 millions discharges, 73,000 were identified as having been admitted primarily due to schizophrenia. The average length of stay was 13.5 days, with 90% of time spent in a designated psychiatric bed. Over 90% were discharged within one month, most (∼80%) to home without documentation of further services. The mean cost per stay (including physician fees) was $8,963. Most (68%) patients had only one admission, and 96% had less than five in one year, leading to annual hospitalization cost per schizophrenic patient of $13,854.
CONCLUSIONS: Of schizophrenic patients admitted to an acute general hospital, the majority are admitted only once per year, spend their stay in a designated psychiatric unit bed, and are discharged within two weeks. Although these patients may have subsequent admissions to another type of inpatient facility, the majority are not transferred to such a facility at the time of discharge.     

Hospital reimbursement patterns among patients with surgical wound infections following open heart surgery

Of the more than 200,000 patients who undergo open heart surgery annually in the United States, 2% to 10% will develop a post-operative infection related to their surgery. The economic impact of such infections on hospitals under the prospective payment system is unclear. To study the effect of such infections on hospital costs and reimbursement patterns, we compared case patients with controls of similar age, sex, urgency of surgery and type of surgery. The postoperative stay for cases was significantly longer than for matched controls (26.8 days and 8.3 days, respectively; p = .0002). The mean hospital cost for case admissions ($25,957) was twice as high as for control admissions ($12,795) (p = .0002). Cases resulted in an average net loss to the hospital of $2,344 per patient, while controls yielded an average net gain of $3,196 per patient (p = .02). We conclude that hospitals have substantial financial incentives to minimize the incidence of postoperative wound infections associated with open heart surgery.     

Case shifting and the Medicare Prospective Payment System.

We assessed impacts of the Medicare Prospective Payment System (PPS) during its first two years of operation (1984-85) on 467 hospitals using data from the Commission on Professional and Hospital Activities and from the American Hospital Association. Medicare discharges as a per cent of total discharges remained constant between 1983 and 1985, but the per cent of uninsured patients increased, especially at large public hospitals. The number of Medicare and total discharges per hospital declined. The number of complex diagnosis related groups (DRGs) increased, both for Medicare and non-Medicare. This trend began before the implementation of PPS and affected all types of hospitals. There was also an appreciable increase in case mix types of hospitals. There was also an appreciable increase in case mix severity within specific DRGs during 1980-85. The proportion of total patients received from or transferred to other hospitals rose after 1983, but these increases were very small. The per cent of Medicare patients admitted through the emergency room increased, especially after 1983. By contrast, the share of total non-Medicare admissions through the emergency room (ER) remained stable. Although the growth of the number of uninsured and Medicare patients admitted through the ER predate PPS, they may be influenced by it and warrant further monitoring.     

Evaluation of access,a primary care program for indigent patients: inpatient and emergency room utilization

We analyzed the impact of a program that provides indigent patients with free primary care on inpatient admissions, emergency room (ER) visits, and resulting charges in 91 patients before and after admittance into the program.There was a decrease in ER visits after enrolling in the program (1.89 versus 0.83 visits per year; p < 0.0001). This difference translated into mean ER charges of $1174 vs. $717 (p = 0.0007), and a decrease in charges of $41,587 per year. The charges for the program (outpatient visits and laboratory) were $23,141. Entry into the program had no effect on inpatient admissions, which averaged 0.07 admissions per year both before and after admission to the program.Indigent patients enrolled in a complimentary primary care program had significantly decreased per-year ER utilization rates and charges. The program had no effect on inpatient admissions. By conservative estimate, the program decreased ER charges by approximately $18,000 per year secondary to decreased ER utilization.     

Utilization of hospital services by cardiovascular patients, Alberta, Canada.

Using hospital discharge records, and United States DRG (diagnosis related groups) data, we studied hospital utilization by cardiovascular patients, associated hospital expenditures, and the per capita cost of treating cardiovascular diseases in Alberta, Canada between 1971 and 1986. Expressed in constant 1984 Canadian dollars, the estimated total hospital cost increased from $84 million in 1971 to $131 million in 1986; during this period the Province of Alberta spent about $51 Canadian per resident each year for cardiovascular hospital services. It was noted that rural residents consumed a higher volume of resources per capita than their urban counterparts. A patient origin-destination analysis indicated an increasing dependence of rural patients on urban hospitals for secondary or tertiary care, underscoring the effects of medical technology on referral patterns.     

Skin cancer has a large impact on our public hospitals but prevention programs continue to demonstrate strong economic credentials

Objectives: While skin cancer is still the most common cancer in Australia, important information gaps remain. This paper addresses two gaps: i) the cost impact on public hospitals; and ii) an up‐to‐date assessment of economic credentials for prevention. Methods: A prevalence‐based cost approach was undertaken in public hospitals in Victoria. Costs were estimated for inpatient admissions, using State service statistics, and outpatient services based on attendance at three hospitals in 2012–13. Cost‐effectiveness for prevention was estimated from ‘observed vs expected’ analysis, together with program expenditure data. Results: Combining inpatient and outpatient costs, total annual costs for Victoria were $48 million to $56 million. The SunSmart program is estimated to have prevented more than 43,000 skin cancers between 1988 and 2010, a net cost saving of $92 million. Skin cancer treatment in public hospitals ($9.20～$10.39 per head/year) was 30‐times current public funding in skin cancer prevention ($0.37 per head/year). Conclusions: At about $50 million per year for hospitals in Victoria alone, the cost burden of a largely preventable disease is substantial. Skin cancer prevention remains highly cost‐effective, yet underfunded. Implications for public health: Increased funding for skin cancer prevention must be kept high on the public health agenda. Hospitals would also benefit from being able to redirect resources to non‐preventable conditions.     

Room for Improvement: Gastrointestinal Disorders and Payment Errors

The physician is central to deciding whether a patient requires acute inpatient hospital treatment and is also responsible for appropriately documenting the record which permits accurate diagnostic-related grouping (DRG) coding. An area of particular concern both nationally and in New York State has been patients admitted with gastrointestinal (GI) disorders; specifically, DRGs 174 (GI hemorrhage with complication) and 182 (esophagitis, gastroenteritis, and miscellaneous digestive disorders age > 17 with complication comorbidity). A baseline sample of 600 cases from fiscal year (FY) 2006 was selected from 20 hospitals and underwent review for both admission necessity and DRG assignment. The results were disseminated to the hospitals. In addition, hospitals with a >10% error rate were required to implement an improvement plan. A re-measurement sample of 300 cases was taken from FY 2007 for review. The aggregate error rate was 13.3% at baseline and decreased to 8.0% on re-measurement (P < 0.05). Admission denials decreased from 8.0 to 4.7% related primarily to DRG 182. Errors in DRG assignment decreased from 5.7 to 3.3% related primarily to DRG 174. Of note, the greatest improvement in both admission and DRG errors was seen in the hospitals required to implement a formal improvement plan. These data show that a program that includes emphasis on education of physicians on the importance of admission criteria and careful documentation of the record can reduce both inappropriate admissions and improve accuracy of DRG assignment.     

Nursing: a major hospital cost component.

Selected studies of nursing costs demonstrate a wide variation per patient-day and per patient stay within the same DRG. These differences could reflect either actual differences in nursing practice or methodological differences in calculating practice costs. We examined several alternative methods to find hospital nursing costs of the same group of patients. Measures of patient illness--AS-SCORE severity of illness, Relative Intensity (RIMs), MacLeod nursing intensity, and a per diem measure--were compared for variations in nursing cost. Various definitions of nursing cost itself also were compared using the same patients. Two approaches to defining nursing cost elements--by nursing unit and by hands-on patient care-are discussed. Several nursing cost studies reporting data for DRG 121 (myocardial infarction with complications and/or comorbidity) were compared with our data. The nursing care costs in several studies of these same patients varied from $706 to $1,778 per stay (a 60 percent difference); reasons for these cost differences are discussed. It is suggested that at least part of this variability reflects methodological differences. Cost data should be reported carefully to facilitate comparisons with the results of other studies. Efforts should begin toward designing nursing cost studies using comparable measures and cost-finding methodologies.     

Public hospital admissions for treating complications of clinical care: incidence,costs and funding strategy

Objective: To quantify the frequency of, and the costs and payments associated with, admissions for treatment of injuries and illnesses that are consequences of care. Data sources: Routinely‐coded 2005/06 public hospital inpatient data from Victoria, Australia (1.25 million admissions) and corresponding patient‐level cost data (1.04 million admissions). Payments reflected DRG‐based prospective rates. Study design: Retrospective analysis of admissions with principal diagnoses that specify adverse events arising as a direct consequence of healthcare. Results: 1.5% (15,336) of the costed admissions specifically treat an injury or illness arising from medical or surgical care, consuming 2.74% of hospital prospective payments and representing $89.3 m (2.84%) of total reported costs. 1.4% (17,429) of all public hospital admissions and 2.82% of hospital prospective payments (estimated cost‐$101.5 m per year) are committed to treating complications of care. Private residences or aged care facilities are the source of 84.9% (14,804) of these admissions. Inpatient death was the outcome in 0.7% (118) of these admissions. Implications: Admissions for treating complications of care represent a small, relatively expensive, proportion of hospital admissions, which account for disproportionate levels of hospital costs and funding. A policy option providing incentives to reduce the incidence and costs of complications arising from care includes allocating all costs arising from transferred (re)admissions back to the original episode of care and developing a suite of specific DRGs to fund admissions for treatment of complications.     

Shifting costs from high-cost to low-cost diagnosis-related groups?

Hospitals are commonly compared with each other within diagnosis-related group (DRG) categories. Administrators infer that hospitals with a higher cost per case within a DRG are less efficient than hospitals with a lower cost per case after case mix and severity adjustment. The authors assess whether hospitals that carry a heavy load of high-cost DRGs potentially distribute the added expenses of treating these patients onto their lower cost DRGs using data gathered from the 47 hospitals in the University Hospital Consortium database between January 1994 and December 1995. The results indicate that given standard hospital allocation practices, some of the costs associated with high-cost patients were likely shifted downward, thereby inflating the cost per case for less expensive patients. As researchers adopt more benchmarking methodologies, it is important to recognize that standard accounting practices in which cost shifting from one class of patient to another may impair the ability to understand the actual cost structure for classes of patients.     

Financial effects of an influenza pandemic on US hospitals

We estimate the financial effects of an influenza pandemic on US hospitals, including the cost of deferring elective admissions and the cost of uncompensated care for uninsured patients. Using US pandemic planning assumptions and national data on health care costs and revenues, a 1918-like pandemic would cause US hospitals to absorb a net loss of $3.9 billion, or an average $784,592 per hospital. Policymakers should consider contingencies to ensure that hospitals do not become insolvent as a result of a severe pandemic.     

Underresourced hospital infection control and prevention programs: penny wise, pound foolish?

OBJECTIVES: To estimate the cost of healthcare-associated infections (HAIs) in a network of 28 community hospitals and to compare this sum to the amount budgeted for infection control programs at each institution and for the entire network. DESIGN: We reviewed literature published since 1985 to estimate costs for specific HAIs. Using these estimates, we determined the costs attributable to specific HAIs in a network of 28 hospitals during a 1-year period (January 1 through December 31, 2004). Cost-saving models based on reductions in HAIs were calculated. SETTING: Twenty-eight community hospitals in the southeastern region of the United States. RESULTS: The weight-adjusted mean cost estimates for HAIs were $25,072 per episode of ventilator-associated pneumonia, $23,242 per nosocomial blood stream infection, $10,443 per surgical site infection, and $758 per catheter-associated urinary tract infection. The median annual cost of HAIs per hospital was $594,683 (interquartile range [IQR], $299,057-$1,287,499). The total annual cost of HAIs for the 28 hospitals was greater than $26 million. Hospitals budgeted a median of $129,000 (IQR, $92,500-$200,000) for infection control; the median annual cost of HAIs was 4.6 (IQR, 3.4-8.0) times the amount budgeted for infection control. An annual reduction in HAIs of 25% could save each hospital a median of $148,667 (IQR, $74,763-$296,861) and could save the group of hospitals more than $6.5 million. CONCLUSIONS: The economic cost of HAIs in our group of 28 study hospitals was enormous. In the modern age of infection control and patient safety, the cost-control ratio will become the key component of successful infection control programs.     

Inpatient costs of endophthalmitis evaluated for the whole of France

Background

Endophthalmitis is a severe condition that requires hospitalization with at least day care. Information on the incidence rate, costs and consequences of endophthalmitis is scarce.

Objective

To estimate the number of patients with endophthalmitis hospitalized in France, as well as the average costs and hospital budget consequences.

Methods

French Programme de Médicalisation des Systèmes d’Information (PMSI) data for 2006, derived from the official DRG classification, were analysed. Data were extracted concerning the following primary diagnoses: ‘purulent endophthalmitis’, ‘other endophthalmitis’ and ‘endophthalmitis associated with another disease’. Two durations of hospitalization were compared: the actual duration and a weighted DRG duration. The cost of hospitalization was weighted by the average DRG cost + daily hospital costs × the difference between the actual and weighted DRG days in hospital. All costs are presented in €, year 2007 values.

Results

A total of 1518 patients (mean age 68.7 years; 47.1% male) experienced 1725 hospitalizations for endophthalmitis, including 1416 cases (82.1%) admitted to public hospitals. The majority of patients (79.1%) were classified by DRG codes that did not specify endophthalmitis (DRG 02M03Z). Most patients (1342) were given a drug injection and 510 underwent vitrectomy. Four patients died in hospital and 75 were transferred to other hospitals. The actual duration of hospitalization for endophthalmitis in public hospitals was 8.1 days (mean), whereas the average weighted DRG duration was 5.1 days, which underestimated the actual duration by 3 days. The average hospital cost was €3688 per patient, totalling €6 361 119 per annum for all public and private hospitalizations in France, including €223 723 as day care. If hospital funding was wholly based on DRG tariffs, the budget for endophthalmitis would be severely underestimated. The DRG inclusion of ’severe acute ocular infections’ as a proxy for endophthalmitis dramatically underestimated its true cost by approximately 30%.

Conclusion

For health economic evaluations, it is inappropriate to use DRG classifications as proxies for endophthalmitis. Expressed more generally, hospitalization cost analyses should not be based on any specific DRG, but always on the clinically relevant primary diagnosis. The PMSI clustering algorithm underestimates the hospital budgets required for endophthalmitis. Lastly, the PMSI (exhaustively reporting all hospitalizations) is best suited to capturing yearly endophthalmitis incidence rates, average costs and national health expenditure.     

A Rural Cancer Outreach Program Lowers Patient Care Costs and Benefits Both the Rural Hospitals and Sponsoring Academic Medical Center

The Rural Cancer Outreach Program (RCOP) between two rural hospitals and the Medical College of Virginia's Massey Cancer Center (MCC) was developed to bring state-of-the-art cancer care to medically underserved rural patients. The financial impact of the RCOP on both the rural hospitals and the MCC was analyzed. Pre- and post-RCOP financial data were collected on 1,745 cancer patients treated at the participating centers, two rural community hospitals and the MCC. The main outcome measures were costs (estimated reimbursement from all sources), revenues, contribution margins and profit (or loss) of the program. The RCOP may have enhanced access to cancer care for rural patients at less cost to society. The net annual cost per patient fell from $10,233 to $3,862 associated with more use of outpatient services, more efficient use of resources, and the shift to a less expensive locus of care. The cost for each rural patient admitted to the Medical College of Virginia fell by more than 40 percent compared with only an 8 percent decrease for all other cancer patients. The rural hospitals experienced rapid growth of their programs to more than 200 new patients yearly, and the RCOP generated significant profits for them. MCC benefited from increased referrals from RCOP service areas by 330 percent for cancer patients and by 9 percent for non-cancer patients during the same time period. While it did not generate a major profit for the MCC, the RCOP generated enough revenue to cover costs of the program. The RCOP had a positive financial impact on the rural and academic medical center hospitals, provided state-of-the-art care near home for rural patients and was associated with lower overall cancer treatment costs.     

Health care reform and Connecticut's non-profit hospitals

The recent federal Health Care Reform Act signed into law by President Obama is expected to lead to greater patient volumes at non-profit hospitals in Connecticut (and throughout the country). The financial implications for these hospitals depend on how the costs per patient are expected to change in response to the anticipated higher patient volumes. Using a regression analysis of costs with annual data on 30 Connecticut hospitals over the period 2006 to 2008, we find that there are considerable differences between outpatient and inpatient unit cost structures at these hospitals. Based on the results of our analysis, and assuming health care reform leads to an overall increase in the number of outpatients, we would expect Connecticut hospitals to experience lower costs per outpatient treated (economies of scale). On the other hand, an influx of additional inpatients would be expected to raise unit costs (diseconomies of scale). After controlling for other cost determinants, we find that the marginal cost of an inpatient is about $8,000 while the marginal cost of an outpatient is about $44. This disparity may provide an explanation for our finding that the effect of additional patient volumes overall (combining inpatient and outpatient) is an increase in hospitals' unit costs.     

Hospital competition in a national health service: Evidence from a patient choice reform

We study the impact of exposing hospitals in a National Health Service (NHS) to non-price competition by exploiting a patient choice reform in Norway in 2001. The reform facilitates a difference-in-difference approach due to plausibly exogenous (geographical) variation in pre-reform market structure. Employing rich, administrative data, covering the universe of hospital admissions from 1998 to 2005, we estimate models with hospital and treatment (DRG) fixed-effects and use only emergency admissions to limit patient selection issues. The results show that hospitals in more competitive areas have a sharper reduction in AMI mortality but no effect on stroke mortality. We also find that exposure to competition reduces all-cause mortality, shortens length of stay, but increases readmissions, though the effects are small in magnitude. In years with high (DRG) prices, the negative effect on readmissions almost vanishes. Finally, exposure to competition tends to reduce waiting times and increase admissions, but the effects must be interpreted with care as the outcomes include elective treatments.     

Impact of aging on hospital caseload

PURPOSE: The progressive ageing of the population has led to a rise in the number of hospital admissions among people older than 64 years. The present study analyses the impact of this phenomenon comparing the case-mix of patients older and younger than 65 years. METHODS: An analysis of the case-mix of all patients admitted to two acute hospitals of Barcelona Spain has been performed using the minimum basic data set of hospital discharges during 1997. The patients were grouped according to diagnosis-related groups (DRG). The characteristics of disease severity and complexity (admissions through emergencies department, DRG average weight, Charlson comorbidity index, average length of stay adjusted by case-mix, percentage of patients with an abnormal length of stay, readmissions and mortality rates were compared between the group of patients of 0-64 years and the group of 65 years and over. A further analysis was carried out for three subgroups of the aged patient population: 65-74, 75-84 and > 84 years. RESULTS: The patients group of 65 years and over presented, in comparison with the younger than 65 qulaction, a higher average weight (1.16 vs 0.96), a higher percentage of admissions through emergency department (49.2% vs 44.4%), more comorbidity (Charlson's Index of 0.98 vs 0.66), a higher average length of stay adjusted DRG (9.4 vs 8.1), a higher percentage of patients with an abnormal length of stay (4.7% vs 3.2%), a higher readmissions percentage (8.6% vs 7.5%) and a higher mortality (6.3% vs 1.6%). All observed differences between the two groups were statistically significant. The analysis of the three subgroups of patients of 65 years and over showed that the variables admissions through the emergency department, length of stay and rate of mortality were significantly related to ageing, while the factor of complexity of comorbidity remained stable for all the subgroup of patients. CONCLUSIONS: The case-mix of patients older than 65 years presents some characteristics associated with a higher complexity, severity and comorbidity, which imply more hospitalization days in relation to younger patients. Hospitals and the health care system at large should design specific strategies to face the fast and progressive ageing of patients admitted to hospitals, since this means a relevant change of the case-mix and the profile of health care requirements.