Date Published: June 27, 2019
Publisher: Public Library of Science
Author(s): Nathaniel Lee, Laura V. White, Flora P. Marin, Naomi R. Saludar, Marietta B. Solante, Rosario J. C. Tactacan-Abrenica, Rugaiya W. Calapis, Motoi Suzuki, Nobuo Saito, Koya Ariyoshi, Christopher M. Parry, Tansy Edwards, Sharon E. Cox, Joao Felipe Mota.
The Philippines is ranked 3rd 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.
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. 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.
Tuberculosis (TB) is the leading cause of death from a single infectious agent . Malnutrition, in this case “under-nutrition” is both a risk factor for and complication of active TB disease [2–4]. Clinical wasting and under-nutrition are common clinical findings in patients infected with Mycobacterium tuberculosis (MTB) and are associated with mortality and adverse outcomes [5–7]. A recent systematic review  identified under-nutrition as a consistently demonstrable risk factor for death in TB patients on treatment, both within 2 months of treatment initiation as well as late deaths after completion of treatment.
We enrolled 360 individuals from a total of 1476 admissions with known or suspected TB (Fig 1). The main reasons for exclusion were weekend (Friday night to Saturday) or holiday admissions (34.3%), or the patient being too unwell to participate, give consent or refused (40.3%).
This study establishes the association between under-nutrition assessed using MUAC with risk of inpatient death in this acutely unwell adult population. In this study, there was no apparent effect of diabetes. Further research is required in different populations to optimize MUAC cut-offs to predict risk of death and develop suitable nutritional interventions in active TB disease.