Patients in the rapid test group were more quickly documented in the chart as having HIV (.8 vs. 6.4 days, p<.001), placed on an HIV service sooner (1.4 versus 6.9 days, P<.001), initiated outpatient follow-up sooner (21.5 versus 49.5 days, p=.05), and had less unawareness of their HIV status (0 vs. 16%, P=.002). There was no significant difference between the two groups in time from admission to empiric treatment or diagnosis of an opportunistic infection. Patients who received the rapid test did have a lower length of stay (6.4 versus 13.2 days, P<.001). Although much of this difference was due to higher number of ICU stays in the conventional group, in multivariate analysis conventional testing still increased length of stay significantly, OR 5.4 days (2.5, 8.3).
This study suggests that patients who are tested with rapid HIV testing can lead to more efficient inpatient treatment of the complications of HIV, improved patient awareness of HIV status, and quicker outpatient follow-up. These findings have ramifications not just to the inpatient management of patients with HIV but to general public health efforts to reduce the spread of HIV infection.
Nevertheless, these results must be interpreted with caution. They reflect the experience of one institution situated in an area with a high prevalence of HIV. Some degree of selection bias is suggested by the higher presence of ICU admissions in the conventional testing group. The multivariate analysis attempted to control for confounding factors, but the possibility remains that other unrecognized factors may have influenced results. The authors do note that an analysis of patients in the rapid test group stratified by whether the test was performed for screening or by referral of the physician did not demonstrate a statistically significant difference in length of stay. This finding provides further support that the sicker patients which triggered the rapid test had shorter lengths of stay on account of the rapid test and not simply because they were sicker.
As recognized by the authors, physicians in routine practice rely on surrogate markers of HIV infection, most notably a patient’s CD4 count, and thus it is not surprising that the rapid test did not affect time to empiric treatment or diagnosis of opportunistic infection. If treatment did not differ, then explaining the longer length of stay remains an unexplained puzzle. The fact that the two groups were equally matched socially and psychiatrically leaves open the possibility that it was actual knowledge of the HIV test result—and not its effect on treatment—that drove the longer length of stay.
One possibility not suggested by the authors is that definitive knowledge of HIV status helped to mobilize patient discharge. If there were legitimate concerns of follow-up, physicians may have delayed discharge in order to receive HIV test results. Alternatively, some patients may have resisted discharge until receiving test results and the development of a more concrete plan. It would be interesting to know if the time to follow-up for the two groups would be the same if the 16% who did not know their HIV status at discharge were excluded. This suggests that knowledge of HIV status drives follow-up time and would lend some support to the notion that patient discharge was delayed for test results and clarification of the follow-up treatment plan.
Even putting aside the difference in length of stay, the difference of rapid testing on improved knowledge of HIV status and quicker follow-up is likely real and meaningful. Although this study was not designed to assess the impact of this knowledge on patient behavior, immediate knowledge of HIV status during hospitalization may translate to decreased transmission as patients alter their behavior and lends further credibility to the utility of rapid HIV testing in conjunction with conventional methods in the management of inpatients. TH