BackgroundMissing data are common in medical research, which can lead to a loss in statistical power and potentially biased results if not handled appropriately. Multiple imputation (MI) is a statistical method, widely adopted in practice, for dealing with missing data. Many academic journals now emphasise the importance of reporting information regarding missing data and proposed guidelines for documenting the application of MI have been published. This review evaluated the reporting of missing data, the application of MI including the details provided regarding the imputation model, and the frequency of sensitivity analyses within the MI framework in medical research articles.MethodsA systematic review of articles published in the Lancet and New England Journal of Medicine between January 2008 and December 2013 in which MI was implemented was carried out.ResultsWe identified 103 papers that used MI, with the number of papers increasing from 11 in 2008 to 26 in 2013. Nearly half of the papers specified the proportion of complete cases or the proportion with missing data by each variable. In the majority of the articles (86%) the imputed variables were specified. Of the 38 papers (37%) that stated the method of imputation, 20 used chained equations, 8 used multivariate normal imputation, and 10 used alternative methods. Very few articles (9%) detailed how they handled non-normally distributed variables during imputation. Thirty-nine papers (38%) stated the variables included in the imputation model. Less than half of the papers (46%) reported the number of imputations, and only two papers compared the distribution of imputed and observed data. Sixty-six papers presented the results from MI as a secondary analysis. Only three articles carried out a sensitivity analysis following MI to assess departures from the missing at random assumption, with details of the sensitivity analyses only provided by one article.ConclusionsThis review outlined deficiencies in the documenting of missing data and the details provided about imputation. Furthermore, only a few articles performed sensitivity analyses following MI even though this is strongly recommended in guidelines. Authors are encouraged to follow the available guidelines and provide information on missing data and the imputation process.Electronic supplementary materialThe online version of this article (doi:10.1186/s12874-015-0022-1) contains supplementary material, which is available to authorized users.

Mothers who report depressed mood face significantly more life challenges, both environmental stressors related to poverty and other problematic behaviors. More proximal, postnatal depressed mood appears to have a larger influence on their children, compared with antenatal depressed mood. (PsycINFO Database Record

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Objective: Examine resiliency among a South African population cohort of children of mothers living with HIV (MLH) and mothers without HIV (MWOH) in low-income townships over the first 5 years of life. Design: A cluster randomized controlled intervention trial evaluating child resiliency and the effects of home visiting in township neighborhoods from pregnancy through 5 years postbirth. Methods: The population of pregnant women in 24 matched neighborhoods were recruited and randomized by neighborhood to a standard care condition (n ¼ 594) or a paraprofessional home visiting intervention condition (n ¼ 644). Mothers and children were assessed at 2 weeks, 6, 18, 36, and 60 months postbirth (92 – 84% follow-up; 10.2% mortality). Resilient children were identified based on consistently meeting global standards for growth, cognitive functioning, and behavior. Maternal HIV status (n ¼ 354 MLH; n ¼ 723 mothers without HIV MWOH), intervention condition, maternal risks, caretaking, sociodemographic characteristics, and neighborhood were examined as predictors of child resiliency over time using analysis of variance, chi-square analyses, and Fisher’s exact tests, where appropriate. Results: None of HIV-seropositive children (n ¼ 17) were resilient; 19% of 345 HIV- exposed but uninfected children of MLH were resilient, a rate very similar to the 16% among MWOH. Resiliency was significantly associated with lower income, food security, not having a live-in partner, and the absence of maternal risk (i.e., not being depressed, using alcohol, or being a victim of intimate partner violence). Being randomized to a home visiting intervention, maternal breastfeeding for at least 3 months and attending a preschool crèche were also unrelated to resiliency. Although matched pairs of neighborhoods had similar rates of resilient children, resiliency varied significantly by neighborhood with rates ranging from 9.5 to 27%. Conclusion: We set a new standard to define resiliency, as consistently recommended by theoreticians. Although seropositive children are not resilient, uninfected children of MLH are as resilient as their peers of MWOH. Typical protective factors (e.g., home visiting, breastfeeding, preschool) were unrelated to resiliency over the first 5 years of life.