Severe malnutrition in infants under six months old: outcomes and risk factors in Bangladesh

Location: Bangladesh

What we know: The World Health Organization (WHO) recommends that infants under six months with uncomplicated severe acute malnutrition (SAM) are treated in the community.

What this article adds: A prospective cohort study was undertaken on infants under six months (<6m) in Barisal district, Bangladesh, of one group of 77 infants with SAM (weight for length z-score <-3 and/or bipedal oedema) and 77 non-SAM infants, all enrolled at four to eight weeks of age and followed up at six months. Maternal education and satisfaction with breastfeeding were among factors associated with SAM. Duration of exclusive breastfeeding was shorter at enrolment (3.9 ±2.1 vs. 5.7 ± 2.2 weeks, P < 0.0001) and at age six months (13.2 ± 8.9 vs. 17.4 ± 7.9 weeks; P = 0.0003) among SAM infants. Despite referral, only 13 (17%) reported for inpatient care and at six months 18 (23%) infants with SAM still had SAM and 3 (3.9%) died. In the non-SAM group, one child developed SAM and none died. Current inpatient-focused treatment strategies have limited practical effectiveness due to poor uptake of inpatient referral. WHO recommendations of outpatient-focused care for malnourished but clinically stable infants <6m must be tested. Breastfeeding support must be central to future interventions but may be insufficient alone. Better case definitions are needed in this age group.

Severe acute malnutrition (SAM) affects around four million infants under six months old (infants <6m) worldwide, but evidence underpinning their care is of very low quality. To inform future research, the objectives of this study were to identify risk factors for infant <6m SAM and describe the clinical and anthropometric outcomes of treatment with current management strategies. A prospective cohort study was undertaken involving two groups of infants aged four to eight weeks (the age when future interventions to treat infant <6m SAM will be anticipated to begin). One group comprised 77 infants with SAM (defined as weight-for length z-score (WLZ) <-3 and/or bilateral nutritional oedema); the other comprised 77 age- and sex-matched infants who were not severely malnourished. Exclusions were infants from twin/multiple pregnancies and those with obvious congenital anomalies that could affect feeding. The primary outcome was the proportion of infants who died or who had SAM at follow-up at age six months. Secondary outcomes were changes in and absolute values of WLZ, weight-for-age z-score (WAZ) and length-for-age z-score (LAZ). SAM ‘case’ infants and non-SAM infants were identified by household visits in Barisal district, Bangladesh; anthropometric measurements were taken according to standard guidelines and were recorded electronically.

By six-month endline, statistically significant differences were apparent between SAM and non-SAM infants: daily weight gain was better among the SAM group (8.6 vs 4.3 g/kg/day, P<0.0001) and mid-upper arm circumference (MUAC) increase was greater (35.7 vs 13.2mm, P <0.0001), WLZ change was greater (2.0 vs -0.24, P<0.0001) and WAZ change was greater (0.9 vs -0.4, P<0.0001). However, there was a similar decline in LAZ of 0.6 z-scores in both groups. Maternal education and satisfaction with breastfeeding were among factors significantly associated with SAM, as well as age at time of enrolment into the study, years of maternal schooling and access to household electricity. Duration of exclusive breastfeeding was shorter at enrolment (3.9 ±2.1 vs. 5.7 ± 2.2 weeks, P < 0.0001) and at age six months (13.2 ± 8.9 vs. 17.4 ± 7.9 weeks; P = 0.0003) among SAM infants. Despite referral, only 13 (17%) reported for inpatient care and at six months, 18 (23%) infants with SAM still had SAM and 3 (3.9%) died. In the non-SAM group, one child developed SAM and none died. Maternal mental health was worse among mothers of SAM infants with a higher mean self-reporting questionnaire (SRQ) score at baseline (8.4 ± 3.6 versus 6.8 ±3.8, P = 0.003).

Results show that most infants identified as having SAM at four to eight weeks of age did not access inpatient treatment when referred as per national protocol. Deaths in this age group were higher than in the control group, but not as high as have been previously reported in inpatient studies. Although only one quarter of those with SAM at enrolment still had SAM at six months, other anthropometric deficits were marked, including significantly more stunting (62% vs. 15%), more severe stunting (40% vs. 0%) and more underweight (68% vs. 7%). The authors discuss the fact that few of the SAM infants who were referred to inpatient care actually accessed that care is reminiscent of past experiences with older SAM-affected children. Before community-based management of acute malnutrition (CMAM), when only inpatient-based care was available, coverage for such programmes was poor due to the high direct and opportunity cost of treatment. However efficacious such inpatient-only treatments might be, their overall effectiveness and public health impact is severely limited by the low numbers of eligible patients accessing care they need. Also reminiscent of the shift from inpatient-only care to CMAM outpatient-focused models, some professionals now are concerned about the safety of outpatient care for SAM infants <6m. Addressing this concern, it is reassuring that despite the minimal (or no direct) treatment, over three quarters of infants with SAM at four to eight weeks baseline no longer had SAM at age 6 months. This may represent catch-up growth, as suggested by greater rates of weight gain in the SAM group, and emphasises infancy as a dynamic and important period of life. Nevertheless, interventions are needed: ex-SAM infants had considerably more other anthropometric deficits than infants who did not have SAM at baseline, suggesting ongoing vulnerability.

The authors conclude that the current inpatient-focused treatment approaches to infant <6m SAM are sub-optimal. Some form of treatment is needed, as suggested by infants in the SAM group being more underweight and more stunted than non-SAM controls. However, the fact that many showed weight catch-up and no longer had SAM by six months suggest that it is reasonable to classify infants in the same way as older children with SAM, recognising that some are sufficiently clinically stable (“uncomplicated SAM”) to be safely managed in community-based programmes, as recommended by WHO². In terms of risk factors, sub-optimal breastfeeding is key and breastfeeding support is likely central to future interventions, but may be insufficient alone. Further interventions should evaluate the effectiveness of a package of interventions which also addresses wider issues, such as home environment and maternal support/maternal mental health. Finally, the authors call for better ways of identifying at-risk infants. Current case definitions of SAM are widely used, but do not fully capture the many possible reasons why an infant may be small. Improved classification and understanding of underlying aetiology in individual cases may allow more tailored treatments with greater probability of success.