Hospital Charges for People with AIDS in Washington State: Utilization ...

Hospital Charges for People with AIDS in Washington State: Utilization of a Statewide Hospital Discharge Data Base WILLIAM E. LAFFERTY, MD, SHARON G. HOPKINS, DVM, JEANNE HONEY, JANICE D. HARWELL, MA, PHYLLIS C. SHOEMAKER, AND JOHN M. KOBAYASHI, MD, MPH Abstract: We analyzed Washington State inpatient hospital utilization for 165 AIDS (acquired immunodeficiency syndrome) cases with 344 hospitalizations from July 1984 through December 1985. We found that mean charges per hospitalization were $9,166 and mean length of stay was 13.3 days. In addition, evaluation of two diagnosis-related groups (DRGs 079 and 398) commonly used for

AIDS hospitalizations showed that AIDS hospitalizations were substantially more expensive than non-AIDS hospitalizations within the same diagnosis-related group. AIDS-specific diagnosis-related groups may be necessary to achieve a balance between inpatient charges and reimbursements. (Am JPublic Health 1988; 78:949-952.)

Introduction Early in the course of the AIDS (acquired immunodeficiency syndrome) epidemic, medical care for AIDS cases was provided primarily by a small core of physicians in major urban medical centers. As the disease spread geographically, AIDS care decentralized. Previously reported evaluations of AIDS medical costs have been limited to epicenters of AIDS care, San Francisco and Massachusetts, and calculated charges based on a single medical care facility with a special interest in AIDS."2 These studies reported diagnosis-todeath inpatient costs of approximately $27,000 to $46,000 per case and served to refute the early estimate of $147,000 for lifetime inpatient costs which had been calculated by Hardy, et al.3 In addition to the lack of statewide cost data, the effect of Medicaid reimbursement policies based on diagnosisrelated groups (DRGs) in the era of AIDS has remained largely unstudied. To evaluate costs of AIDS care in both urban and rural hospitals and examine the effects of diagnosis-related group reimbursement policies, we obtained statewide data containing inpatient charges for AIDS care, method of payment by cases, and the DRGs for AIDS cases in Washington State.

The Commission Hospital Abstract Reporting System (CHARS) is a computerized listing that uses the International Classification of Diseases (9th Revision, Clinical Modification [ICD-9]) to code hospital discharges in Washington State. CHARS data were submitted by hospital medical records departments to the State Hospital Commission for all hospital discharges in Washington, excluding those from military facilities. One health maintenance organization (HMO) did not begin abstracting discharges until July 1985. These data were submitted within 45 days of hospital discharge. The permanent database excludes identifiers such as name and chart number but includes birth date, mortality status, dates of admission and discharge, hospital charges, hospital, county, method of payment, and five diagnoses coded according to the ICD-9 code and the DRG. Data for 750,000 hospital discharges were available for the period July 1, 1984 through December 31, 1985. No ICD-9 diagnosis in use during this study was originally intended to specify AIDS-related conditions. Therefore, 18 diagnoses of conditions often linked to human

Methods From July 1, 1984 through December 31, 1985, the AIDS Surveillance Units of the Communicable Disease Epidemiology Section/Division of Health and the Seattle-King County Department of Public Health collected case reports of Washington State residents meeting the Centers for Disease Control (CDC) definition of AIDS.4 In Washington, passive surveillance, active hospital telephone surveillance, and monthly meetings with sentinel physicians and other health care providers are the predominant case-finding tools. In February 1986, hard copy records were computerized using AIDS Reporting System (ARS) software supplied by the CDC. Address reprint requests to Sharon G. Hopkins, DVM, AIDS Epidemiologist, Seattle-King County Department of Public Health, AIDS Surveillance Unit, 1116 Summit, #200, Seattle, WA 98101. Ms. Honey is an Administrative Specialist/Research and Evaluation Assistant with the Health Department. Dr. Lafferty is Director of AIDS Surveillance; Ms. Harwell is a Health Field Worker; Ms. Shoemaker is a Research Analyst; and Dr. Kobayashi is State Epidemiologist; all are affiliated with the Washington State Department of Social and Health Services, AIDS Surveillance Unit. This paper, submitted to the Journal October 19, 1987, was revised and accepted for publication January 26, 1988. © 1988 American Journal of Public Health 0090-0036/88$1.50

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immunodeficiency virus (HIV) infection were selected for this study (Table 1). These included codes 279.19 (other deficiency of cell-mediated immunity) and 136.3. (Pneumocystis carinii pneumonia, PCP), considered the most common diagnoses denoting AIDS-related illnesses. Any CHARS listing containing at least one of the 18 diagnoses was compared to the ARS AIDS case registry by matching birth dates. Reviews of patient hospital records were performed to validate matches. By identifying discharges of cases present on both ARS and CHARS, we determined the percentage of any diagnostic code that indicated reported AIDS cases. Discharges coded with either 279.19 or 136.3 that did not match the birth date of a reported case were reviewed to determine if the hospitalization was AIDS-related. Medical records of ARS cases not found in CHARS were reviewed to determine the reason the discharge was not in CHARS. Statistical analysis of hospital utilization data was performed using two-tailed t tests and one-way analyses of variance. Results

Validation of Data Bases Completeness of CHARS Reporting-The Washington State AIDS registry listed 182 AIDS cases who were alive for all or part of the study period. Ninety per cent of these cases were homosexual males between 20 and 49 years old. One hundred and thirty-seven (75 per cent) of the living cases had hospital discharges located on CHARS. Of the 182 living cases, 149 (82 per cent) had AIDS diagnosed during the study 949

LAFFERTY, ET AL. TABLE 1-Frequency of Diagnosis Codes In 750,000 Hospital Discharges Compared to Discharges of Confirmed AIDS Cases

Potentially AIDS-related Diagnoses (ICD-9 code) Other deficiency of cell-mediated immunity (279.19) Pneumocystis carinii pneumonia (136.3)

Cryptococcal meningitis (321.0) Cryptococcosis unspecified (117.5) Toxoplasmosis meningoencephalitis (130.0) Cytomegalic inclusion disease (079) Mycobacteria other than M. tuberculosis (031) Progressive multifocal leukoencephalopathy (046.3) Other malignant neoplasm of skin

(173) Histoplasmosis (115) Candidiasis (112) Herpes simplex virus (054) Interstitial pneumonitis (516.8) Unspecified immune deficiency (279.3) Reticulosarcoma (200.0) Malignant neoplasm of the brain (191) Other lymphosarcoma (200.8) Unspecified T-cell defect (279.4) Total frequency of ICD-9 diagnoses

4019 Hospital Discharges of 2,467 Patients

231 (77)

181 27 37

111 (61) 9 (33) 12 (32)

7

74

2 (29) 13 (18)

42

6 (14)

7

1 (14)

552 15 653

60 (11) 1 (7) 38 (6) 26 (2) 2 (2) 1 (2) 1 (1) 2 (0) 0 (0) 0 (0) 516

120 53 124

1,064

68 4

4,385

period and, of these, 117 (79 per cent) were found on CHARS. The 32 cases (21 per cent) diagnosed during the period but missing from CHARS included three for whom AIDS was diagnosed out-of-state, 14 diagnosed as outpatients, and one case that was not investigated. The remaining 14 missing cases had inpatient diagnoses in Washington State but five were diagnosed in institutions exempt from CHARS reporting. Thus, of these 149 cases, 127 should have appeared on CHARS (149 minus the three out-of-state, 14 outpatient diagnoses, and five cases in exempt hospitals). Our methods detected 117 of the 127 (92 per cent). Of the 10 missing cases, medical record review detected charting errors in ICD-9 codes in three cases. In six of the missing cases, ICD-9 codes and date of birth were correct in the medical record, hence data entry errors were suspected. In one case the hospital of admission was incorrect on the ARS data base and therefore the discharge could not be located by hospital record review. ICD-9 Classification of HIV Disease-Abstracting 18 AIDS-associated ICD-9 diagnosis codes yielded 4,385 total diagnoses. These were present singly or in combination among 4,019 hospitalizations representing 2,476 patients. Only two diagnoses, codes 279.19 (other deficiency of cellmediated immunity) and 136.3 (P. carinii pneumonia), were more common in hospitalizations of reported AIDS cases than in other hospitalizations (Table 1). Medical record review of 159 of the 165 cases coded with 279.19 showed that 130 (82 per cent) were reported AIDS cases meeting the then-current (1985 revision) CDC case definition. One unreported case was detected. Nine (6 per cent) were cases reported as residents of other states, five (3 per cent) were cases of presumptively diagnosed AIDS, and 12 (8 per cent) were cases meeting the 1987 revision of the CDC case definition for HIV-related neurologic disease or wasting syndrome5 but did not have a specific opportunistic infection or malignancy diagnosed. Two cases (1 per cent) were not HIV-related. Similarly, medical record review of 144 of the 149 cases coded with 136.3 showed that 93 (62 per 950

12/31/85

286 Discharges of 137 Confirmed AIDS Cases (%)

299

1,058

TABLE 2-Statewide Data on Inpatient Charges and Length of Stay for Confirmed Cases of AIDS (N = 165) followed from 7/1/84 to Mean

Overall (n

=

Stay (days)

9,166 + 14,431

13.3 + 17.0

13,696 ± 19,100

16.0 + 11.5

6,318 ± 9,727

11.4 + 19.0

344)

Hospitalizations for PCP (n = 124) All Other Hospitalizations (n = 220)

Mean

Charges ($)*

*Excludes hospitalizations from HMOs.

cent) were reported AIDS cases, two (1 per cent) were presumptively diagnosed AIDS, five (3 per cent) were AIDS cases from another state, and 43 (29 per cent) were not HIV-related. One additional unreported case was detected. Only seven reported AIDS cases (plus one additional in an out-of-state case) found by the diagnosis 136.3 were also not

detected by 279.19.

Statewide Utilization Data

One hundred and sixty-five patients (157 from evaluation of code 279.19 and eight additional from 136.3) having 344 HIV-related hospitalizations were identified on CHARS and verified through medical record review. Statewide mean inpatient charges were $9,166 per hospitalization and mean length of stay was 13.3 days (Table 2). The mean number of hospitalizations per case was 2.1. For each criteria, the median values were lower, reflecting the impact of several long and expensive hospitalizations. The mean length of time these cases appeared on the data base was 7.2 months (range 1-19 months, calculated from the earliest admission date to the latest discharge date or to the end of the data base in surviving patients). From these data, we estimate annual inpatient charges of $32,081 per case, reflecting an estimated 3.5 hospitalizations per follow-up year. Comparing hospitalizations for Pneumocystis carinji pneumonia (PCP) to those for all other AIDS-related conditions showed that PCP admissions resulted in longer and more expensive stays. Mean charges for a PCP hospitalization were $13,696 and the mean length of stay was 16.0 days, compared to $6,318 and 11.4 days for other diagnoses. King County, which has 31 per cent of Washington State's population and includes the state's largest urban area (Seattle), reported 78 per cent of the cases in this study. The remainder of the state is predominantly rural. When AIDSrelated hospitalizations inside and outside King County were compared, it was found that the ages of cases were similar (36 vs 34 years) as were the primary diagnoses (68 per cent vs 65 per cent presenting with P. carinii pneumonia), but the mean total inpatient charges per hospitalization were lower in King County ($637/day) than elsewhere in the state ($877/day). A higher proportion of hospitalizations outside of King County were covered by Medicaid (49 per cent vs 30 per cent, rate ratio = 1.81, 95% CI = 1.28, 2.56). Charges for AIDS vs Non-AIDS Hospitizations within the Same

DRG

For the 344 hospitalizations in 165 cases, a total of 70 different DRGs were used. Two DRGs, codes 398 (reticuloendothelial and immunity disorders in those over 70 years or with complications) and 079 (lung inflammation in those over 70 or with complications), were used for 66 and 64 HIV-related hospitalizations, respectively. While code 079 in AJPH August 1988, Vol. 78, No. 8

AIDS HOSPITAL CHARGES, WASHINGTON STATE TABLE 3-Comparison of AIDS Hospftallatlons to Non-AIDS Hospitalizations for DRG 079 and 398 DRG 079a

AIDS 64

n =

Mean age (years) % male Predominant diagnosis Mean charge ($) Median charge ($) Mean stay Median stay

38 100 136.3 (100%)

14,830 7,545 15.2 14.0

DRG 398b

Non-AIDS n = 62

65 50 482- (50%)

7,057 4,610

AIDS n = 66

36 97 279.19 (98%)

9,416 7,105

10.8 7.8

17.2 14.0

Non-AIDS n = 39

49 54

288d (69%) 4,548 3,008 7.4 5.6

aLung inflammation, >70 years or with complications bReticuloendotelial and immunity disorders, >70 years or with complications CBacterial pneumonia

dAgranulocytosis

AIDS cases exclusively represented PCP, code 398 was used for a variety of HIV-related conditions. For each of these DRGs, confirmed cases with AIDS were compared to cases on CHARS without AIDS (Table 3). For DRG 079, the mean age of non-AIDS cases was older, 50 per cent were female, and the most common ICD-9 diagnosis was bacterial pneumonia (50 per cent). In contrast, the AIDS cases were all male and all had ICD-9 diagnoses reflecting PCP. Within the DRG 079, the hospital charges for AIDS were substantially higher and lengths of stay substantially longer when compared to people with similar conditions who did not have AIDS. Ofthe 62 hospitalizations with the DRG code 079 in people without AIDS, 23 (37 per cent) of these were for PCP caused by iatrogenic immunodeficiency or underlying malignancy. These 23 cases were verified by chart review not to have AIDS. The mean charge per hospitalization for these cases was $4,936, indicating again that PCP in people with AIDS is more expensive to treat than it is in people without AIDS. Results were similar when evaluating the DRG 398 where the predominant primary diagnosis was deficiency of cell-mediated immunity in AIDS cases (code 279.19) and agranuloycytosis (code 288) in cases that did not have AIDS. The mean charges were $9,416 for AIDS cases and $4,548 for those without AIDS. Discussion Our study performed several related functions. We compared the AIDS case registry maintained on ARS software with the CHARS data base and showed that reporting of AIDS patients who had been hospitalized in Washington State was largely complete. Even if the six uninvestigated hospitalizations suspected of having AIDS on the basis of ICD-9 diagnoses were all unreported cases, local AIDS reporting would still reflect 96 per cent of diagnosed cases. In addition, we calculated that during the study period the 1985 CDC case definition (which excluded HIV dementia/encephalopathy complex, wasting syndrome, and presumptive cases) underestimated the incidence of AIDS in hospitalized patients by 11 per cent. More recent surveys of King County physicians and disability registers indicate that the current incidence of disabling HIV-related disease in Washington State is at least 30 per cent of the number of AIDS cases that met the AIDS case definition in use prior to September 1987 (Lafferty and Hopkins, unpublished data). This difference may be due to the progression of HIV illness in seropositive people who were asymptomatic at the time of this study or AJPH August 1988, Vol. 78, No. 8

may reflect the impact of outpatient diagnoses on the future number of reported AIDS cases. Comparison of ARS to CHARS showed that the CHARS data base did not contain one-fourth of the cases registered in ARS and thus would underestimate the incidence of AIDS if used alone. The nature of the data base, rather than our methodology, accounted for most of the AIDS cases missing from CHARS (i.e., outpatient, out-of-state, and exemptinstitution diagnoses). Hospital record review showed that the data contained in CHARS were accurate and that certain ICD-9 codes had a high probability of selecting AIDS cases. In October 1986, the ICD-9 coding system was changed to contain rubrics specific for HIV disease.6 We expect this revision, once validated, will increase the utility of our CHARS method. Our estimated yearly inpatient charges of $32,081 per case were greater than mean lifetime inpatient charges of $27,571 reported from San Francisco,' but less than the yearly inpatient charges of $42,517 reported from Massachusetts.2 While the study periods were similar (1984 data in San Francisco and 1984-85 data in Massachusetts and Washington State), our study cohort differed in fundamental ways from those of the San Francisco and Massachusetts reports. The San Francisco study looked at patients who received all their care at San Francisco General Hospital, a facility long-established and well-versed in AIDS care. The Massachusetts study looked at 45 patients who received care from a group of AIDS specialists at a single hospital. In contrast, our study included almost all AIDS patients hospitalized during an 18-month period in Washington State hospitals, whether the hospital had seen one AIDS case or was a major referral center. Analysis of costs from a mix of 20 urban and rural institutions showed that the charges per hospitalization and per day were greater outside of our major population center despite similar lengths of stay. More cases in King County lacked a third party payment mechanism due to the relatively fewer patients who qualified for Medicaid at the time of hospitalization. This difference may reflect the delays in establishing Medicaid eligibility that occur in urban centers with larger case loads. These delays are particularly problematic for AIDS patients because of their short survival time and the magnitude of their medical needs between diagnosis and death. Although reimbursement policies will vary between regions, our study raises serious concerns about existing DRGs as they are applied to AIDS hospitalizations. We showed that AIDS cases cost more than non-AIDS cases who 951

LAFFERTY, ET AL.

qualify for the same DRG. In Washington State, when the billed amount is 1.5 times the basic DRG payment or is over $12,000 (whichever is greater), the claim is paid on an outlier basis at a higher amount. Admissions that cost more than the average but less than the outlier threshold are those that are likely to exceed reimbursement.7 If these cases are clustered in certain hospitals, as they can be with AIDS, consistent revenue losses will occur. The effect may be greatest in institutions, such as public health hospitals, most dependent on medical assistance reimbursement. For example, for DRG 079 the mean overall Washington State reimbursement is $4,705 per hospitalization when outliers are excluded (Division of Medical Assistance, personal communication). This amount approximates the median charge ($4,610) for nonAIDS cases but is about $3,000 less than the median charge for AIDS cases. Thus, AIDS-specific DRGs or cost-based reimbursement may be necessary as the majority of these cases will not qualify for outlier reimbursement. Regional differences in health care use and the payment of these services may be significant.8 In our study as well as the studies from San Francisco and Massachusetts,",2 AIDS patients were overwhelmingly homosexual males, yet nationally only two-thirds of cases are related exclusively to homosexual behavior.9 Our cost, utilization, and source of payment data may not reflect trends in areas where a greater proportion of AIDS cases occur in intravenous drug users, women, and children. Furthermore, the impact of antiviral chemotherapy on AIDS care costs has yet to be assessed. These factors highlight the need for systems that can generate regional cost data repeatedly over time and can adapt to a rapidly changing scene. We think that relatively automated

hospital discharge data bases are a cost-effective way to contribute to this effort. ACKNOWLEDGMENTS This study was supported by CDC AIDS Surveillance Grant #U62/CCU000993-02. The authors thank Drs. H. Hunter Handsfield, Robert W. Wood, and Steve Ostroff for reviewing the manuscript and giving helpful advice. Leigh Krueger, MPH, provided statistical assistance, and Judith Mentzer assisted with data collection. We gratefully acknowledge Dr. Richard Dicker's help in project design, and the cooperation of all the infection control practitioners and medical records personnel who made complete data collection possible.

REFERENCES 1. Scitovsky AA, Cline M, Lee PR: Medical care costs of patients with AIDS in San Francisco. JAMA 1986; 256:3103-3106. 2. Seage GR III, Landers S, Barry A, et at: Medical care costs of AIDS in Massachusetts. JAMA 1986; 256:3107-3109. 3. Hardy AM, Rauch K, Echenberg D, et al: The economic impact of the first 10,000 cases of the acquired immunodeficiency syndrome in the United States. JAMA 1986; 255:209-211. 4. Centers for Disease Control: Revision of the Case Definition of Acquired Immunodeficiency Syndrome for National Reporting-United States. MMWR 1985; 34:373-375. 5. Centers for Disease Control: Revision of the CDC Surveillance Case Definition for Acquired Immunodeficiency Syndrome. MMWR 1987; 36:3S-15S. 6. US Department of Health and Human Services: International Classification of Diseases, 9th Rev. Clinical Modification, Addendum. Washington, DC: DHHS, 1986. 7. Kasten BL: The Physicians DRG Handbook. Ed. 1. Hudson, Ohio: Lexi-Comp Inc., 1987; 13-14. 8. Andrulis DP, Beers VS, Bentley JD, Gage LS: The provision and financing of medical care for AIDS patients in US public and private teaching hospitals. JAMA 1987; 258:1343-1346. 9. Institute of Medicine: Confronting AIDS. Washington, DC: National Academy Press, 1986; 86.

Call for Papers: International Conference on Alcohol, Drugs and Traffic Safety The 11th International Conference on Alcohol, Drugs, and Traffic Safety, hosted by the National Safety Council, has issued a call for papers and contributions for the conference to be held October 24-27, 1989 in Chicago, Illinois. The conference is soliciting papers from a broad spectrum of disciplines, including law, medicine, chemistry, physics, information and computer sciences, political science, economics, sociology, psychology, education, engineering, law enforcement, cultural anthropology, and others. The program will be structured on the basis of papers submitted. The principal purpose of these conferences is to form common understanding among the conferees through systematic information exchange. The Conference planners emphasize that papers, however specialized, on alcohol, other drugs and traffic safety are welcome. The deadline for submission of abstracts is October 1, 1988. Proceedings of the 10 prior conferences, held approximately every three years, provide an important contribution to world information in this field. Co-hosts of the 1989 conference include: American Bar Association, American Medical Association, Association for Advancement of Automotive Medicine, National Association of Independent Insurers, and Northwestern University Traffic Institute. To receive information about the conference and instructions about submission of abstracts, contact Al Lauersdorf, T89 Secretariat, National Safety Council, 444 N. Michigan Avenue, Chicago, IL 60611.

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