We performed the feasibility and reliability of the MOS to measure HRQoL among HIV positive and HIV negative patients with pulmonary TB receiving care at public and private hospitals in urban, Uganda. The key finding in this study of 133 patients with pulmonary TB is that the MOS in measuring HRQoL performed well on the psychometric indicators and this instrument appears to be an effective tool for evaluating HRQoL among TB patients. The scale demonstrated acceptable internal consistency among TB patients with different stages of treatment. Evaluation of constructs revealed remarkable differences in the functional status and well-being among TB patients at different stages of treatment, hospital settings, and gender. However, no differences were seen by HIV status.
Findings in this study suggest that TB patients have poor HRQoL at the time of diagnosis and this impression appear to be marked among patients attending public compared to private health institutions particularly for perceived health, bodily pain, role function, and health distress. However, patients receiving care from public health institution had substantial relative increase in HRQoL scores for QoL subscale, physical health summary score, and visual analogue scale following TB therapy compared to patients who received care from private institution. This suggest that patients receiving care in public health institutions appear to catch-up in HRQoL to those receiving care in private institutions and that TB therapy improves HRQoL regardless of treatment setting.
In this study, men of older age had poor HRQoL score relative to women of similar age group suggesting that men were sicker compared to women. This probably reflects on the health seeking habits for men which could be that by the time men present, their disease is advanced. We found no differences in HRQoL scores by HIV status probably because HIV impacts minimally on HRQoL among patients with TB; however, this requires further evaluation in prospective studies and after teasing the effect of HIV disease severity.
Results of the psychometric testing of the MOS in a population of patients with pulmonary TB in the present study were similar to prior studies that culturally adapted it into the local language- Luganda in Uganda among HIV-infected women . The reliability coefficients for the MOS subscales in prior studies among HIV-infected women were above 0.70 except for role functioning at 0.43 and vitality at 0.64. Similarly in the present study, all MOS subscales had coefficients above 0.70 except role functioning that had 0.65. Further evidence for validity of our findings is shown by the high correlation of each dimension of the MOS with the dimension measured concurrently using the VAS.
There is paucity of research on HRQoL among TB patients in the African population, and particularly few have evaluated HRQoL using generic standardized or disease-specific quality of life instruments. The score profiles in our study population were quite similar to those reported in a cross-sectional study from South Africa . For example, the mental health score was 55.6 ± 12.8 for the South African study compared to 61.6 ± 25.5 for the present study. This suggests that HRQoL may be affected similarly by TB disease across cultural contexts. Compared to the South African study, the major strengths with our study is the heterogeneity of the study population that included patients from different hospital settings, patients at different stages of TB therapy, HIV positive, and HIV negative. Thus our study findings are generalizable to a wide-range of patients particularly countries in sub-Saharan Africa with a high burden of TB and HIV.
Our study was not without limitations including lack of test re-test reliability for us to comment on the stability of the MOS HRQoL scores across time. In addition, the study design was cross-sectional in nature and thus the associations may not be causal. Further, our findings were limited by lack of data on severity of HIV disease which might affect HRQoL scores . Nevertheless, our findings may provide insight to the future predictive validity of the study instrument among TB patients because participants were enrolled at different stages of treatment.
In conclusion, this study provides evidence that the MOS instrument is a valid and reliable measure of HRQoL among TB patients and can be used in a wide variety of study populations and settings. Further, findings revealed that treatment improved HRQoL among TB patients. However, there were differences in HRQoL among TB patients by hospital settings, and by gender among older patients.