The results of this initial test provide evidence for acceptable reliability and validity of the Thai versions of the MOS-HIV and SF-12 as measures of HRQOL among HIV+ patients in Northern Thailand. Both questionnaires were successfully translated/culturally adapted into the Thai language. The low refusal rate (4%) and high response rate for all questionnaires (99-100%) point to good acceptability by patients.
In this study, trained interviewers adopted a modified face-to-face technique where the questionnaire was read out-loud to the patient, with the patient then filling in his or her response. This modified technique was well-received by both interviewers and interviewees and allowed interviewees to ask questions or have issues clarified during the interview process. By filling out the answers themselves, however, confidentiality was preserved. Furthermore, in Thai and other Asian cultures, deference to authority (such as the interviewer) and the desire to minimize interpersonal conflict may influence patient response in interviewer-administration as interviewees will try to answer questions in a way they think will be socially acceptable to the interviewer. Self-administering the questionnaires may have allowed interviewees to be more truthful in their answers.
Psychometric performance was consistent with previous studies and suggested that there was adequate internal consistency for the MOS-HIV [12–17]. Evidence for construct validity was demonstrated by the relationship between summary scores and relevant clinical variables, including symptom distress score, number of days spent in bed, and days of reduced activity. Interestingly, CD4 count was the only variable which was not significantly correlated to either physical or mental health summary scores. This is consistent with most previous research studies [17, 18] and is unsurprising as many patients with low CD4 on HAART may be asymptomatic, while some of those responding to treatment may have diminished scores due to side effects of HAART therapy. Also as expected, the physical health scores were better able to distinguish between the variables examined, which reflect physical rather than mental functioning.
It was interesting to note that the MOS-HIV performed slightly better than the SF-12 in its ability to discriminate between known groups with a greater number of significant p-values (4 vs. 3) and p-values approaching significance. However, one must be cautious in interpreting these results, given the different samples of patients completing the two questionnaires.
Because we were interested in the ultimate usability of health-related quality of life questionnaires in clinical settings, we selected tools that differed in length. The more comprehensive MOS-HIV provides more precise estimates of a range of specific issues. However, it is more time-consuming than the SF-12 (11 vs 5 minutes on average). Investigators and clinicians should weigh these factors in selecting between the two alternatives.
A study published in 2004 evaluating the psychometric properties of an independently translated version of the MOS-HIV found a high level of internal consistency reliability of multi-item scales with all multi-item scales achieving Cronbach's alpha of 0.7 or above . In the 2004 study, respondents were recruited only from PLWHA support or self-help groups. Our study was conducted in community-based hospital settings and recruited respondents from patients at their regular visits, which may capture a more representative sample of HIV+ people in Northern Thailand. Notably, many patients had very low (<300) CD4 counts. However, the overwhelming majority (98%) of patients participating in our study were receiving antiretroviral therapy, which was rare during the time of the study. At the time of this study, there was no translated version of the SF-12 available. However, there is now an official translation of this instrument. Future studies should be conducted to confirm the performance of the SF-12 Thai version.
Limitations of our study included an inability to test for responsiveness, as all questionnaires were tested among patients at a single time point. Since patients completed either the MOS-HIV or the SF-12 and not both, we were unable to perform head-to-head comparisons of the two instruments or correlate them to each other. Although our study indicated that the MOS-HIV performed slightly better than the SF-12 in its ability to discriminate between known groups, this could be a random effect since different groups filled out different questionnaires. In addition, because we did not have access to patient medical records or providers, we asked patients to self-report their CD4 count. There was individual variability in the extent to which patients could report these. However, we only used this variable to test the construct validity of the quality of life scales. Nonetheless, it is likely to have introduced additional random error into the estimate of CD4 count and attenuated the correlation with quality of life scores.
There is often little time in clinic settings for health care personnel to administer questionnaires. Outside of clinical trials, there is little attention paid to measurements of HRQOL. However, more health care workers are recognizing that HRQOL can play a large impact on HIV treatment and care, especially in the area of compliance with complicated and potentially toxic drug regimens. As both questionnaires were well-accepted by patients in this pilot test, in our own ongoing studies, we are using the MOS-HIV at yearly intervals or at certain milestones in a patient's care, such as immediately before commencing antiretroviral therapy. At other visits, a shorter tool, such as the SF-12 can provide a snapshot of the patient's QOL. By focusing a part of the clinical encounter on QOL, the health care team is given an opportunity to address issues that may not be captured during a standard HIV clinic visit. Most importantly, the patient is provided a dedicated outlet to bring attention to concerns that may affect his or her care with the team.
In conclusion, the Thai versions of the SF-12 and MOS-HIV were acceptable, valid, and reliable among HIV+ Thai patients interviewed in a clinical outpatient setting. As more Thais are able to access ARV through national health care programs designed to cover treatment for PLWHA's, attention to QOL will become increasingly important to provide effective and patient-centered care. The SF-12 and MOS-HIV are promising tools that may be used in clinical environments to help assess patient's HRQOL and guide both patients' and providers' decision-making.