Study objective: To determine and compare rates of diarrhea in patients receiving an antiretroviral regimen containing lopinavir-ritonavir versus nelfinavir and in patients who received these drugs sequentially.
Design: Retrospective cohort analysis.
Setting: Hospital-based human immunodeficiency virus (HIV) clinic.
Patients: Four hundred one participants in the HIV Atlanta VA Cohort Study who were prescribed lopinavir-ritonavir or nelfinavir from 1996-2002.
Measurements and main results: Chart review identified episodes of diarrhea that potentially were associated with an antiretroviral agent. Data collected included antidiarrheal agents dispensed, baseline viral load and CD4+ cell counts, demographic variables, and previous therapy Diarrhea associated with an antiretroviral regimen occurred in 175 (49%) of 354 patients receiving nelfinavir and 17 (17%) of 99 patients receiving lopinavir-ritonavir (p < 0.001). Treatment for the diarrhea occurred in 118 (33%) of 354 patients receiving nelfinavir and 9 (9%) of 99 receiving lopinavir-ritonavir (p < 0.001). Patients in the lopinavir-ritonavir group were more likely to have received highly active antiretroviral therapy and azithromycin than patients receiving nelfinavir, and they had lower baseline CD4+ cell counts (p < or = 0.01 for each comparison). The average number of months/person-year of diarrhea treatment was 2.0 for the nelfinavir group and 0.13 for the lopinavir-ritonavir group. Of the 10 antiretroviral-naive patients who received lopinavir-ritonavir, none needed treatment for diarrhea, whereas 78 (36%) of 217 antiretroviral-naive patients who received nelfinavir required treatment for diarrhea. Of the 52 patients who had been taking nelfinavir and were switched to lopinavir-ritonavir, they were more likely to start antidiarrheal treatment while taking nelfinavir (14 [27%]) than while receiving lopinavir-ritonavir (3 [6%]) (p = 0.004).
Conclusions: Patients receiving lopinavir-ritonavir were significantly less likely to have diarrhea or to require treatment for diarrhea than patients receiving nelfinavir. The same results occurred when the drugs were given to the same patients sequentially (nelfinavir followed by lopinavir-ritonavir). The diarrhea associated with lopinavir-ritonavir was less frequent, less severe, and shorter in duration than diarrhea associated with nelfinavir.