The impact of diabetes on tuberculosis treatment outcomes: a systematic review.

BACKGROUND: Multiple studies of tuberculosis treatment have indicated that patients with diabetes mellitus may experience poor outcomes.We performed a systematic review and meta-analysis to quantitatively summarize evidence for the impact of diabetes on tuberculosis outcomes. METHODS: We searched PubMed, EMBASE and the World Health Organization Regional Indexes from 1 January 1980 to 31 December 2010 and references of relevant articles for reports of observational studies that included people with diabetes treated for tuberculosis. We reviewed the full text of 742 papers and included 33 studies of which 9 reported culture conversion at two to three months, 12 reported the combined outcome of failure and death, 23 reported death, 4 reported death adjusted for age and other potential confounding factors, 5 reported relapse, and 4 reported drug resistant recurrent tuberculosis. RESULTS: Diabetes is associated with an increased risk of failure and death during tuberculosis treatment. Patients with diabetes have a risk ratio (RR) for the combined outcome of failure and death of 1.69 (95% CI, 1.36 to 2.12). The RR of death during tuberculosis treatment among the 23 unadjusted studies is 1.89 (95% CI, 1.52 to 2.36), and this increased to an effect estimate of 4.95 (95% CI, 2.69 to 9.10) among the 4 studies that adjusted for age and other potential confounding factors. Diabetes is also associated with an increased risk of relapse (RR, 3.89; 95% CI, 2.43 to 6.23). We did not find evidence for an increased risk of tuberculosis recurrence with drug resistant strains among people with diabetes. The studies assessing sputum culture conversion after two to three months of tuberculosis therapy were heterogeneous with relative risks that ranged from 0.79 to 3.25. CONCLUSIONS: Diabetes increases the risk of failure and death combined, death, and relapse among patients with tuberculosis. This study highlights a need for increased attention to treatment of tuberculosis in people with diabetes, which may include testing for suspected diabetes, improved glucose control, and increased clinical and therapeutic monitoring

Stress-induced rise in body temperature is repeatable in free-ranging Eastern chipmunks (Tamias striatus)

In response to handling or other acute stressors, most mammals, including humans, experience a temporary rise in body temperature (T b). Although this stress-induced rise in T b has been extensively studied on model organisms under controlled environments, individual variation in this interesting phenomenon has not been examined in the field. We investigated the stress-induced rise in T b in free-ranging eastern chipmunks (Tamias striatus) to determine first if it is repeatable. We predicted that the stress-induced rise in T b should be positively correlated to factors affecting heat production and heat dissipation, including ambient temperature (T a), body mass (M b), and field metabolic rate (FMR). Over two summers, we recorded both T b within the first minute of handling time (T b1) and after 5 min of handling time (T b5) 294 times on 140 individuals. The mean ∆T b (T b5 – T b1) during this short interval was 0.30 ± 0.02°C, confirming that the stress-induced rise in T b occurs in chipmunks. Consistent differences among individuals accounted for 40% of the total variation in ∆T b (i.e. the stress-induced rise in T b is significantly repeatable). We also found that the stress-induced rise in T b was positively correlated to T a, M b, and mass-adjusted FMR. These results confirm that individuals consistently differ in their expression of the stress-induced rise in T b and that the extent of its expression is affected by factors related to heat production and dissipation. We highlight some research constraints and opportunities related to the integration of this laboratory paradigm into physiological and evolutionary ecology