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Impact of diabetes and smoking on mortality in tuberculosis.

Reed GW, Choi H, Lee SY, Lee M, Kim Y, Park H, Lee J, Zhan X, Kang H, Hwang S, Carroll M, Cai Y, Cho SN, Barry CE, Via LE, Kornfeld H - PLoS ONE (2013)

Bottom Line: Results were compared in TB patients with and without diabetes or smoking history.Diabetes was present in 25% and was associated with greater radiographic severity and with recurrent or relapsed TB.In this cohort, the impact of diabetes on mortality was greater in patients younger than 50 years, compared to older patients.

View Article: PubMed Central - PubMed

Affiliation: Department of Preventive and Behavioral Medicine, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America.

ABSTRACT

Background: Diabetes mellitus is a risk factor for tuberculosis (TB) disease. There is evidence that diabetes also influences TB severity and treatment outcomes but information is incomplete and some published results have been inconsistent.

Methods: A longitudinal cohort study was conducted at the National Masan Tuberculosis Hospital in the Republic of Korea. Subjects presenting with a first episode of TB or for retreatment of TB were followed from enrollment through completion of treatment. Demographic, clinical, and microbiological variables were recorded, along with assessment of outcomes. Results were compared in TB patients with and without diabetes or smoking history. Data were adjusted for gender, age, cohort, educational level and alcohol consumption.

Results: The combined cohorts comprised 657 subjects. Diabetes was present in 25% and was associated with greater radiographic severity and with recurrent or relapsed TB. Diabetes and cigarette smoking independently increased the risk of death in the first 12 months after enrollment. Estimating the combined impact of diabetes and smoking yielded a hazard ratio of 5.78. Only 20% of diabetic subjects were non-smokers; 54% smoked ≥1 pack daily. In this cohort, the impact of diabetes on mortality was greater in patients younger than 50 years, compared to older patients.

Conclusions: In this cohort of Korean patients, diabetes exacerbated the severity of TB disease. Diabetic subjects who smoked ≥1 pack of cigarettes daily were at particularly high risk of death from TB. Strategies to improve TB outcomes could productively focus resources for patient education and TB prevention on the vulnerable population of younger diabetics, particularly those who also smoke.

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Survival estimates.Unadjusted Kaplan-Meier survival curve for all causes of death in diabetic subjects (red lines) and non-diabetic subjects (blue lines) grouped by age ≥50 (dashed lines) or age <50 (solid lines). Separate curves by age (dashed vs. solid) and diabetes (red vs. blue) illustrate the interaction of diabetes and age on survival. For age <50 the separation between diabetic vs. non-diabetic subjects is larger than for age ≥50.
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pone-0058044-g002: Survival estimates.Unadjusted Kaplan-Meier survival curve for all causes of death in diabetic subjects (red lines) and non-diabetic subjects (blue lines) grouped by age ≥50 (dashed lines) or age <50 (solid lines). Separate curves by age (dashed vs. solid) and diabetes (red vs. blue) illustrate the interaction of diabetes and age on survival. For age <50 the separation between diabetic vs. non-diabetic subjects is larger than for age ≥50.

Mentions: Unadjusted survival was 87% in diabetics vs. 94% in non-diabetics during the first year after enrollment and TB treatment at NMTH. The adjusted hazard ratio (HR) for all-cause mortality in diabetic subjects compared with non-diabetic subjects, adjusted for cohort, age, gender and smoking was 2.18 (95% CI: 1.10, 4.34; Table 5). For TB-related deaths, the HR = 1.98 (95% CI: 0.90, 4.35; Table 6). Adjusting for MDR-TB in the all-cause or TB-related mortality models did not change the results appreciably, with HR = 2.40 (95% CI: 1.19, 4.2) for all-cause mortality and HR = 2.06 (95% CI: 0.94, 4.54) for TB-related deaths. This was unsurprising since drug resistance was highly correlated with cohort B that is included in the adjustment. MDR-TB status was missing in approximately 14% of the patients, so data presented in Tables 5 and 6 do not include the adjustment for MDR-TB. TB-related deaths in this study were attributable to respiratory failure, hemoptysis and to extrapulmonary TB (the latter reflecting only 2 of 49 TB-related deaths). Hemoptysis was the cause of death in the first year for 5 of 11 (46%) subjects with diabetes vs. 4 of 18 (22%) non-diabetic subjects, but this did not reach statistical significance. Figure 2 illustrates the unadjusted Kaplan-Meier estimates for all deaths, stratified by the presence or absence of diabetes and by age group. The survival difference between diabetic and non-diabetic subjects occurred mainly within the first 6 months of enrollment and treatment, after which the Kaplan-Meier curves were relatively parallel. The impact of diabetes on all-cause mortality was estimated to be greater in subjects <50 years of age (HR = 3.91 [95% CI: 1.54, 9.98]) than subjects ≥50 years old (HR = 1.12 [95% CI: 0.39, 3.18]). The test of interaction of diabetes and age resulted in p = 0.09 for all deaths. A similar interaction was estimated for TB-related deaths, with the impact of diabetes greater in subjects <50 years HR = 3.7 compared to the impact subjects >50 years, HR = 0.92 (p = 0.10; Fig. S1).


Impact of diabetes and smoking on mortality in tuberculosis.

Reed GW, Choi H, Lee SY, Lee M, Kim Y, Park H, Lee J, Zhan X, Kang H, Hwang S, Carroll M, Cai Y, Cho SN, Barry CE, Via LE, Kornfeld H - PLoS ONE (2013)

Survival estimates.Unadjusted Kaplan-Meier survival curve for all causes of death in diabetic subjects (red lines) and non-diabetic subjects (blue lines) grouped by age ≥50 (dashed lines) or age <50 (solid lines). Separate curves by age (dashed vs. solid) and diabetes (red vs. blue) illustrate the interaction of diabetes and age on survival. For age <50 the separation between diabetic vs. non-diabetic subjects is larger than for age ≥50.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3585219&req=5

pone-0058044-g002: Survival estimates.Unadjusted Kaplan-Meier survival curve for all causes of death in diabetic subjects (red lines) and non-diabetic subjects (blue lines) grouped by age ≥50 (dashed lines) or age <50 (solid lines). Separate curves by age (dashed vs. solid) and diabetes (red vs. blue) illustrate the interaction of diabetes and age on survival. For age <50 the separation between diabetic vs. non-diabetic subjects is larger than for age ≥50.
Mentions: Unadjusted survival was 87% in diabetics vs. 94% in non-diabetics during the first year after enrollment and TB treatment at NMTH. The adjusted hazard ratio (HR) for all-cause mortality in diabetic subjects compared with non-diabetic subjects, adjusted for cohort, age, gender and smoking was 2.18 (95% CI: 1.10, 4.34; Table 5). For TB-related deaths, the HR = 1.98 (95% CI: 0.90, 4.35; Table 6). Adjusting for MDR-TB in the all-cause or TB-related mortality models did not change the results appreciably, with HR = 2.40 (95% CI: 1.19, 4.2) for all-cause mortality and HR = 2.06 (95% CI: 0.94, 4.54) for TB-related deaths. This was unsurprising since drug resistance was highly correlated with cohort B that is included in the adjustment. MDR-TB status was missing in approximately 14% of the patients, so data presented in Tables 5 and 6 do not include the adjustment for MDR-TB. TB-related deaths in this study were attributable to respiratory failure, hemoptysis and to extrapulmonary TB (the latter reflecting only 2 of 49 TB-related deaths). Hemoptysis was the cause of death in the first year for 5 of 11 (46%) subjects with diabetes vs. 4 of 18 (22%) non-diabetic subjects, but this did not reach statistical significance. Figure 2 illustrates the unadjusted Kaplan-Meier estimates for all deaths, stratified by the presence or absence of diabetes and by age group. The survival difference between diabetic and non-diabetic subjects occurred mainly within the first 6 months of enrollment and treatment, after which the Kaplan-Meier curves were relatively parallel. The impact of diabetes on all-cause mortality was estimated to be greater in subjects <50 years of age (HR = 3.91 [95% CI: 1.54, 9.98]) than subjects ≥50 years old (HR = 1.12 [95% CI: 0.39, 3.18]). The test of interaction of diabetes and age resulted in p = 0.09 for all deaths. A similar interaction was estimated for TB-related deaths, with the impact of diabetes greater in subjects <50 years HR = 3.7 compared to the impact subjects >50 years, HR = 0.92 (p = 0.10; Fig. S1).

Bottom Line: Results were compared in TB patients with and without diabetes or smoking history.Diabetes was present in 25% and was associated with greater radiographic severity and with recurrent or relapsed TB.In this cohort, the impact of diabetes on mortality was greater in patients younger than 50 years, compared to older patients.

View Article: PubMed Central - PubMed

Affiliation: Department of Preventive and Behavioral Medicine, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America.

ABSTRACT

Background: Diabetes mellitus is a risk factor for tuberculosis (TB) disease. There is evidence that diabetes also influences TB severity and treatment outcomes but information is incomplete and some published results have been inconsistent.

Methods: A longitudinal cohort study was conducted at the National Masan Tuberculosis Hospital in the Republic of Korea. Subjects presenting with a first episode of TB or for retreatment of TB were followed from enrollment through completion of treatment. Demographic, clinical, and microbiological variables were recorded, along with assessment of outcomes. Results were compared in TB patients with and without diabetes or smoking history. Data were adjusted for gender, age, cohort, educational level and alcohol consumption.

Results: The combined cohorts comprised 657 subjects. Diabetes was present in 25% and was associated with greater radiographic severity and with recurrent or relapsed TB. Diabetes and cigarette smoking independently increased the risk of death in the first 12 months after enrollment. Estimating the combined impact of diabetes and smoking yielded a hazard ratio of 5.78. Only 20% of diabetic subjects were non-smokers; 54% smoked ≥1 pack daily. In this cohort, the impact of diabetes on mortality was greater in patients younger than 50 years, compared to older patients.

Conclusions: In this cohort of Korean patients, diabetes exacerbated the severity of TB disease. Diabetic subjects who smoked ≥1 pack of cigarettes daily were at particularly high risk of death from TB. Strategies to improve TB outcomes could productively focus resources for patient education and TB prevention on the vulnerable population of younger diabetics, particularly those who also smoke.

Show MeSH
Related in: MedlinePlus