Dealing with missing standard deviation and mean values in meta-analysis of continuous outcomes: a systematic review

Background: Rigorous, informative meta-analyses rely on availability of appropriate summary statistics or individual participant data. For continuous outcomes, especially those with naturally skewed distributions, summary information on the mean or variability often goes unreported. While full reporting of original trial data is the ideal, we sought to identify methods for handling unreported mean or variability summary statistics in meta-analysis. Methods: We undertook two systematic literature reviews to identify methodological approaches used to deal with missing mean or variability summary statistics. Five electronic databases were searched, in addition to the Cochrane Colloquium abstract books and the Cochrane Statistics Methods Group mailing list archive. We also conducted cited reference searching and emailed topic experts to identify recent methodological developments. Details recorded included the description of the method, the information required to implement the method, any underlying assumptions and whether the method could be readily applied in standard statistical software. We provided a summary description of the methods identified, illustrating selected methods in example meta-analysis scenarios. Results: For missing standard deviations (SDs), following screening of 503 articles, fifteen methods were identified in addition to those reported in a previous review. These included Bayesian hierarchical modelling at the meta-analysis level; summary statistic level imputation based on observed SD values from other trials in the meta-analysis; a practical approximation based on the range; and algebraic estimation of the SD based on other summary statistics. Following screening of 1124 articles for methods estimating the mean, one approximate Bayesian computation approach and three papers based on alternative summary statistics were identified. Illustrative meta-analyses showed that when replacing a missing SD the approximation using the range minimised loss of precision and generally performed better than omitting trials. When estimating missing means, a formula using the median, lower quartile and upper quartile performed best in preserving the precision of the meta-analysis findings, although in some scenarios, omitting trials gave superior results. Conclusions: Methods based on summary statistics (minimum, maximum, lower quartile, upper quartile, median) reported in the literature facilitate more comprehensive inclusion of randomised controlled trials with missing mean or variability summary statistics within meta-analyses

Extramedullary myeloma in an HIV-seropositive subject. Literature review and report of an unusual case

Myeloma is characterized by monoclonal bone marrow plasmacytosis, the presence of M-protein in serum and/or in urine and osteolytic bone lesions. HIV-seropositive subjects with myeloma are younger at the time of diagnosis of the tumour and usually the myeloma has a more aggressive clinical course than it does in HIV-seronegative subjects

Avaliação do programa de alimentação do trabalhador, no Estado de Pernambuco, Brasil An evaluation of the meals program for workers in Pernambuco State Brazil

Foi avaliado o Programa de Alimentação do Trabalhador (PAT), no que se refere a implantação, funcionamento e resultados em empresas, no Estado de Pernambuco, Brasil. O universo pesquisado abrangeu um total de 130 empresas, sendo 85 inscritas no PAT entre 1977 e 1980 e 45 não inscritas. Neste grupo, a coleta de dados limitou-se ao ano de 1980 e teve como finalidade o estabelecimento de parâmetros para avaliar os indicadores de impacto do Programa. A análise dos cardápios sugere que um reduzido percentual de empresas fornece refeições conforme as exigências mínimas de energia e proteína estabelecidas pela Lei 6.321/76, isto é, um mínimo de 1.400 cal e NDpCal% superior a 6. O exame dos indicadores de impacto nas empresas dos dois grupos sugere que o PAT não modificou o número de acidentes de trabalho, condições de saúde e rotatividade dos trabalhadores; tendo apenas influído no absenteísmo.<br>The establishment, implementation and impact of the Meals Program for Worlkers (MPW) were evaluated in a total of 130 industries in the state of Pernambuco (Northeast Brazil). Of these, 85 had been enrolled in the Program from 1977 to 1980 (experimental group) and 45 had not (control group). The reasons for the implantation or not of the Program, as well as the health conditions, the industrial-accident, absenteeism and turn-over rates among employees, were determined, taking into consideration the economic activity and the size of the industries. In the experimental group the analysis was made from one year before the enrolment in the Program and covered industries which had enjoyed the benefits of 1, 2, 3 or 4 years of fiscal incentive. The data for the control group were collected in 1980 only and were used as a parameter for the evaluation of the impact indicators of the Program. The analysis of the menus suggests that a small number of industries were serving meals in accordance with the minimal amounts of energy and protein recommended by the Law n.&deg; 6.321/76, that is, a minimum of 1,400 cal and NDPcal% higher than 6. The increase in the price of the meal/employee was also determined for the same period of time. It has been demonstrated that government incentives were the motivation for the industries' participation in the Program and that a high percentage of these industries already offered meals to their employees before the Program began. Ignorance of the Law and the administrative indecision were among the reasons for the non-implementation of the Program. A significant number of employees in both groups received less than two legal minimum salaries although the industries of the experimental group offered higher wages to their employees. The analysis of the impact indicators in both groups leads to the conclusion that the number of industrial accidents, health conditions and turn-over rate among employees have remained unchanged, but absenteeism had been reduced by the Program