294   Trends in HIV/AIDS Hospitalization: Rates of Hospitalization and an Examination of Discharge Diagnoses of a Cohort of HIV⁺/ AIDS Patients at UCSD Medical Center (1993—1999).

J. A. Bauer*, W. C. Mathews, and R .E. Barber.
Sch. of Med., Univ. of California San Diego, La Jolla and Sch. of Publ. Hlth., San Diego State Univ., CA.

Background:Hospitalization rates of HIV⁺/AIDS patients in the United States have decreased since the introduction of potent combination therapies. Recent increases in hospitalization rates have been seen in a cohort of HIV-infected patients receiving primary care at UCSD Owen Clinic. The objectives were (1) to examine trends in hospitalization rates by calculating quarterly discharge rates and (2) to examine reasons for hospitalizations by examining discharge diagnosis codes, plasma viral load (pVL), CD4 and demographic characteristics.

Methods:Patients were included if they had at least one outpatient visit at the UCSD Owen Clinic between July 1, 1993 and December 31, 1999. Follow-up began with the first outpatient encounter and ended with the last encounter (inpatient, outpatient, or date of death). Person-time at risk for hospitalization was computed by quarter year, and discharge rates were calculated according to the most recent CD4 and pVL categories and diagnostic codes (CDC A/B/C vs. Other).

Results:A total of 4252 patients met eligibility criteria and contributed a combined follow-up of 69027 person- months. 1337 patients experienced 3452 episodes of hospitalization. Quarterly rates of hospitalization decreased from a peak of 10.2 per 100-person months (p-mo) follow-up in 1993Q3, to a low of 3.1 per 100 p-mo in 1997Q4. However, since 1997Q4, rates have steadily increased to 5.1 per 100 p-mo in 1999Q3 and 8.6 per 100 p- mo in 1999Q4. Since 1995, quarterly mean log pVL of those who where hospitalized has decreased at a rate of 0.045 log/qtr, while between 1993—1999, mean CD4 counts have increased at a rate of 4.2/qtr. Discharge rates involving an HIV-related diagnosis increased, but there was an even larger increase in the rates of hospitalizations involving non-HIV-related conditions.

Conclusions:Hospitalization rates have increased since the beginning of 1998. Over time, there is a trend toward high CD4 and low pVL among the hospitalized. Analysis of discharge diagnoses indicates a slight increase in HIV-related admissions yet larger increases in admissions due to causes unrelated to HIV-indicator conditions.