Review: insufficient evidence exists for oral nutritional supplements as aids for recovery in treated active tuberculosis
In patients being treated for active tuberculosis, do oral nutritional supplements aid recovery?
Included studies compared oral nutritional supplements taken for ⩾4 weeks with no nutritional intervention, placebo, or dietary advice in children or adults being treated with drugs for active tuberculosis. Outcomes included death, positive sputum tests, and weight change.
Cochrane Infectious Disease Group Specialised Register, Medline, EMBASE/Excerpta Medica, LILACS, metaRegister of Controlled Trials (all to Jun 2008), Cochrane Central Register of Controlled Trials (Cochrane Library, Issue 2, 2008), Indian J Tuber (1983 to Jun 2008), and reference lists were searched for randomised controlled trials (RCTs). 12 RCTs (n = 3393) met the selection criteria: 3 used multiple micronutrient supplements, including 1 with additional zinc; 3 used vitamin D; 3 used vitamin A alone or with zinc or selenium; and 1 each used arginine, zinc, high energy protein, and a high cholesterol diet. 5 trials reported adequate allocation concealment, 9 blinded patients using placebo, 5 blinded healthcare providers and outcome assessors, and 11 analysed data from ⩾85% of eligible, randomised patients. 4 RCTs reported mortality, 8 reported results of sputum tests, and 7 reported weight changes.
Meta-analysis showed that multivitamin plus trace element tablets did not differ from placebo for death and that vitamin D reduced positive sputum tests more than placebo or no supplements at 6 weeks, but not 8 weeks (table). Results for other supplements did not show clinically significant differences. Individual trials of protein energy supplements (n = 34), vitamin A plus zinc (n = 80), and multiple micronutrients plus zinc (n = 192) found that supplements were associated with weight gain.
Insufficient evidence exists for the use of oral nutritional supplements as aids for recovery in patients treated for active tuberculosis.
Abba K, Sudarsanam TD, Grobler L, et al. Nutritional supplements for people being treated for active tuberculosis. Cochrane Database Syst Rev 2008;(4):CD006086.
Source of funding: Department for International Development UK.
Abba et al explored the use of oral nutritional supplements in patients being treated for active tuberculosis. Although we might generally expect that improved nutrition would aid recovery from tuberculosis, this review found no consistent effects. All included studies were RCTs, but the nutritional interventions and study outcomes were so varied that they were not comparable, and it is not possible to tease out whether any interventions might be valuable as adjuvant treatment. One study gave patients oral nutritional supplements and advice on reaching a target energy intake; the control group received advice only.1 In this study, the intervention resulted in small improvements in body weight and physical ability. However, the study took place in Singapore, so may not be generalisable to developing countries.
In many studies, the income level of most participants was such that advice to improve intake of high-energy foods would be less useful than in industrialised countries, where disposable incomes are higher. Although the review by Abba et al provides little evidence for the effectiveness of nutritional supplements in patients with active pulmonary tuberculosis, nurses should keep a watchful eye on several large trials currently underway and cited in the review.