Clinical patterns of diarrhea in AIDS: etiology and prognosis.

OBJECTIVE: To define the etiology and prognosis of diarrhea (acute, intermittent or chronic) in AIDS patients.

DESIGN: A retrospective analysis of patients with AIDS and diarrhea. Patterns of diarrhea were defined a priori. Endpoints of interest were etiology, rate of response to therapy, development of chronic diarrhea, and survival probability. Data were analyzed by means of univariate and multivariate tests (chi-square, ANOVA, Student's t test, Kaplan-Meier, logrank and logistic regression analysis).

SETTING: A 170-bed tertiary-care university hospital which is one of the three most important referral centers for AIDS patients in Mexico City.

PATIENTS: The records of the 279 AIDS patients admitted to the hospital between 1983 and 1989 were reviewed; 225 cases were suitable for analysis.

MEASUREMENTS: The presence of a diarrheal episode, the diagnostic studies to which the patient was submitted, the etiology, the response to therapy and the survival time from the point at which the diarrhea started were all recorded. Diarrheal patterns were stratified by clinical patterns and outcomes compared. Possible clinical predictors of chronic diarrhea were analyzed.

RESULTS: Seventy seven percent of the patients suffered at least one diarrheal episode. Diarrhea was in fact the most common AIDS-related complication in our series, and in 51% of the total cases (114/225), it was the first HIV-related symptom. The diarrheal pattern was intermittent in 47% of the cases, chronic in 36% and acute in the remaining 17%. An etiology was established in only 59% of the episodes, and Cryptosporidium was the etiologic agent most frequently isolated (30%). Other opportunistic pathogens prevailed in chronic and intermittent diarrheas. Chronic persistent diarrhea was related to a lower survival probability (60% at one year vs 90% for intermittent and 95% for acute diarrhea, p < 0.0001). When the performance of different diagnostic studies was analyzed, the combination of stool culture, serial parasitic examination and sigmoidoscopy with biopsies provided a high diagnostic accuracy (59%). Regardless of etiology, the rate of therapeutic success was directly related to the previous duration of diarrhea and the absolute lymphocyte count (p < 0.01).

CONCLUSIONS: There are three distinct diarrheal patterns common to AIDS patients. Although the etiologic agents do not vary significantly, each pattern has unique characteristics regarding the timing of presentation, their survival and therapeutic success rate. Such differences should be taken into account when therapeutic trials are designed.