Health Related Quality of Life among Patients with Tuberculosis and HIV in Thailand

INTRODUCTION: Health utilities of tuberculosis (TB) patients may be diminished by side effects from medication, prolonged treatment duration, physical effects of the disease itself, and social stigma attached to the disease. METHODS: We collected health utility data from Thai patients who were on TB treatment or had been successfully treated for TB for the purpose of economic modeling. Structured questionnaire and EuroQol (EQ-5D) and EuroQol visual analog scale (EQ-VAS) instruments were used as data collection tools. We compared utility of patients with two co-morbidities calculated using multiplicative model (U(CAL)) with the direct measures and fitted Tobit regression models to examine factors predictive of health utility and to assess difference in health utilities of patients in various medical conditions. RESULTS: Of 222 patients analyzed, 138 (62%) were male; median age at enrollment was 40 years (interquartile range [IQR], 35-47). Median monthly household income was 6,000 Baht (187 US$; IQR, 4,000-15,000 Baht [125-469 US$]). Concordance correlation coefficient between utilities measured using EQ-5D and EQ-VAS (U(EQ-5D) and U(VAS), respectively) was 0.6. U(CAL) for HIV-infected TB patients was statistically different from the measured U(EQ-5D) (p-value<0.01) and U(VAS) (p-value<0.01). In tobit regression analysis, factors independently predictive of U(EQ-5D) included age and monthly household income. Patients aged ≥40 years old rated U(EQ-5D) significantly lower than younger persons. Higher U(EQ-5D) was significantly associated with higher monthly household income in a dose response fashion. The median U(EQ-5D) was highest among patients who had been successfully treated for TB and lowest among multi-drug resistant TB (MDR-TB) patients who were on treatment. CONCLUSIONS: U(CAL) of patients with two co-morbidities overestimated the measured utilities, warranting further research of how best to estimate utilities of patients with such conditions. TB and MDR-TB treatments impacted on patients' self perceived health status. This effect diminished after successful treatment

Multivariate tobit regression analysis examining determinants of health utility of 222 Thai patients measured using EuroQol 5D instrument, August to October 2009.

<p>TB, tuberculosis; MDR-TB, multi-drug resistant tuberculosis; TB_TX, TB patients receiving TB treatment; MDR_TX, MDR-TB patients receiving MDR-TB treatment; _anyTB_C, patients who had been successfully treated for TB or MDR-TB for ≥6 months; _anyHIV, HIV-infected patients at any stage; TB_TX/HIV, HIV-infected TB patients receiving TB treatment; _anyTB_C/HIV, HIV-infected patients who had been successfully treated for TB or MDR-TB for ≥6 months; ref, referent group.</p><p>*32 Thai Baht = 1 US$.</p

Bland-Altman plot showing the differences between health utilities measured using EuroQol 5D and EuroQol visual analogue scale instruments in relation to the mean of the two measurements in the 222 Thai patients, August to October 2009.

<p>Bland-Altman plot showing the differences between health utilities measured using EuroQol 5D and EuroQol visual analogue scale instruments in relation to the mean of the two measurements in the 222 Thai patients, August to October 2009.</p

Schematic diagram showing estimated difference in health utilities of 222 Thai patients with various medical conditions adjusting for age and monthly household income and measured using EuroQol 5D instrument, August to October 2009.

<p>Schematic diagram showing estimated difference in health utilities of 222 Thai patients with various medical conditions adjusting for age and monthly household income and measured using EuroQol 5D instrument, August to October 2009.</p

Health utilities of 222 Thai patients with various medical conditions measured using EuroQol 5D and EuroQol visual analogue score instruments, August to October 2009.

<p>TB, tuberculosis; MDR-TB, multi-drug resistant tuberculosis; EQ-5D, EuroQol 5D instrument; EQ-VAS, EuroQol visual analogue scale instrument; IQR, interquartile range; SD, standard deviation.</p

Response of 222 Thai patients with various medical conditions to EuroQol 5D instrument, August to October 2009.

<p>TB_TX, TB patients receiving TB treatment; MDR_TX, MDR-TB patients receiving MDR-TB treatment; _anyTB_C, patients who had been successfully treated for TB or MDR-TB for ≥6 months; _anyHIV, HIV-infected patients at any stage; TB_TX/HIV, HIV-infected TB patients receiving TB treatment; _anyTB_C/HIV, HIV-infected patients who had been successfully treated for TB or MDR-TB for ≥6 months.</p