Mid-upper arm circumference predicts death in adult patients admitted to a TB ward in the Philippines: A prospective cohort study

Background

The Philippines is ranked 3^rd globally for tuberculosis incidence (554/100,000 population). The tuberculosis ward at San Lazaro Hospital, Manila receives 1,800–2,000 admissions of acutely unwell patients per year with high mortality. Objectives of this prospective cohort study were to quantify the association of under-nutrition (primary) and diabetes (secondary) with inpatient mortality occurring between 3–28 days of hospital admission in patients with suspected or previously diagnosed TB.

Methods and results

We enrolled 360 adults (≥18 years); 348 were eligible for the primary analysis (alive on day 3). Clinical, laboratory, anthropometric and enhanced tuberculosis diagnostic data were collected at admission with telephone tracing for mortality up to 6 months post-discharge. In the primary analysis population (mean age 45 years, SD = 15.0 years, 70% male), 58 (16.7%) deaths occurred between day 3–28 of admission; 70 (20.1%) between day 3 and discharge and documented total post-day 3 mortality including follow-up was 96 (27.6%). In those in whom it could be assessed, body mass index (BMI) ranged from 11.2–30.6 kg/m² and 141/303 (46.5%) had moderate/severe undernutrition (BMI<17 kg/m²). A sex-specific cut-off for mid-upper arm circumference predictive of BMI<17 kg/m² was associated with inpatient Day 3–28 mortality in males (AOR = 5.04, 95% CI: 1.50–16.86; p = 0.009; p = 0.032 for interaction by sex). The inability to stand for weight/height for BMI assessment was also associated with mortality (AOR = 5.59; 95% CI 2.25–13.89; p<0.001) as was severe compared to normal/mild anaemia (AOR = 9.67; 95% CI 2.48–37.76; p<0.001). No TB specific variables were associated with Day 3–28 mortality, nor was diabetes (HbA1c ≥6.5% or diabetes treatment). Similar effects were observed when the same multivariable model was applied to confirmed TB patients only and to the outcome of all post-day 3 in-patient mortality.

Conclusion

This research supports the use of mid-upper arm circumference for triaging acutely unwell patients and the design and testing of nutrition-based interventions to improve patient outcomes.