Research methods and applications

Healthcare Research

What was the importance/purpose of the study? Describe the inclusion criteria for participant selection in this study.

The premise of the study was that a referral-based outpatient HIV testing system for patients referred from the emergency department (ED) had been ineffective in identifying unrecognized HIV infection due to poor adherence. The study hence aimed to determine whether or not a financial incentive would improve the proportion of referred patients who actually complete testing, counseling, and follow-up in an on-site HIV clinic. The proponents hypothesized that an incentive would increase participation in HIV testing and hence improve the dismal statistics on the high rates of undiagnosed HIV-positive individuals whose only access to medical care is the ED. This would then hopefully improve early detection and prevent a possible epidemic of the disease.

The participants were selected from a "convenience sample" of patients identified as being at risk for HIV infection by ED physicians using CDC (Center for Disease Control) guidelines. These include physical exam findings, laboratory abnormality, and history suggesting immunodeficiency among others. The patients were then classified as low-, moderate-, or high-risk based on these guidelines.

Discuss the financial incentive offered to participants in the study.

The participants were offered $25 to complete HIV testing and counseling at an on-site HIV clinic. They were to attend pre-test counseling, give consent for HIV testing at the lab, and to come back a week later for the results and post-test counseling.

What study design was employed in this study? Would this study be considered an experiment? Explain your answer. What were the results and conclusions of the study?

The study design was described as "prospective controlled," which means that the participants were selected according to pre-set criteria and controlled for one or two factors. In this study, the pre-set criteria were those found in CDC guidelines for HIV case surveillance and the controlled factor, financial incentive. The researchers also classified the study as a "quasi-experiment" (quasi meaning "almost or partly"). A "true" experiment, I believe, should be reproducible, randomized, and have statistically equal control and treatment groups to eliminate possible biases. I think the study fell short as a "true" experiment with respect to the last two criteria because: (1) no randomization procedure was employed in selecting the subjects for the study; and (2) there was no assurance that the treatment and control groups were statistically equal because of the lack of randomization and control of the intra-variation among the physicians in terms of individual differences in their selection of referees. This being said, the current study is no less credible than a "true" experiment.

Demographically, these were the results of the study:

Out of the total 372 patients referred for HIV testing, 60% were considered low-risk, 37% moderate-risk, and 3% high-risk. Out of this number, 32% came from the intervention group (with financial incentive), while 68% came from the two control groups (without financial incentive), with equal percentages of 34% each. Out of the 372 referred patients, only 351 filled up their documents completely and their ethnic distribution was as follows: 40% Hispanics, 32% African-American, 16% white, 5% Asian, and 7% other race.

The results of the study showed that among participants from the low-risk group, 12% completed HIV testing and counseling, versus 6% and 8% from the moderate- and high-risk group, respectively. Overall, 8% from the control group completed testing and counseling versus 23% from the intervention group, which is a "modest increase" according to the researchers. None of those who completed testing was positive for HIV.

With the results controlled for race/ethnicity, i.e., meaning, within the same race/ethnic group, the turnout from the incentive-driven group was significantly higher than the control group. It was also found that whether or not they came from the incentive group, African-Americans and to a lesser degree, Hispanics were significantly less likely to complete testing and counseling compared to the other racial groups.

The researchers concluded that financial incentive resulted in a moderate increase in the number of ED-referred patients completing HIV testing and counseling. They could not say if this method was going to increase the percentage of detection of undiagnosed HIV+ individuals or if it's going to be cost-effective. They recommended point-of-care testing, or testing for HIV right there and then in the ER with rapid, same-day results, to sufficiently impact the number of ethnic minorities testing for HIV infection.

4. In evaluating the research study, what were the weaknesses and strengths of the study? Was the study susceptible to bias? If so, state, define and explain how the study was susceptible to the bias (es).

First of all, the population was not properly defined in the study. It appears that anyone, regardless of age, ethnicity, presenting condition, etc., who presented himself to the ED was a potential subject for the study. Second, the sample was not randomly chosen and was in fact a "convenience sample" composed of participants pre-selected for their increased risk of HIV infection based on the attending physician's assessment. Third, it appears that a physician referral bias was present as evidenced in Table 1 by the differences in the distribution of racial group/ethnicity between the control and intervention groups. Finally, there was no control for possible clustering by physicians, i.e., the study did not control for intra-variation among physicians to account for their individual effects on the referral rate.