Secondary study parameters
weight loss, fat-free mass loss
SECONDARY
Secondary outcomes include percentage of fat-free mass loss, total weight loss, BMI, hand grip strength, and total protein intake measured at baseline, 3, 6, and 12 months of follow-up. These will be analyzed using a generalized least squares model (a linear model for longitudinal data). An unstructured correlation structure for the repeated measurements over time within each subject will be assumed. For each outcome, the treatment effect for the follow-up visits will be modeled by including covariates for treatment, visit, and its interactions. Missings in the outcome vector will be automatically accounted for by the longitudinal model, which allows subjects to remain in the analysis, as long as the outcome has been measured at least at one occasion. Unbiased estimates can still be obtained under the missing at random (MAR) assumption. The analyses will be conducted according to the intention-to-treat principle. As a secondary analysis, a per-protocol analysis will be conducted including only those patients in the treatment group with a cumulative intake of protein supplement of at least 70% during the 6-month intervention period, as indicated by the calendars. Missings in the calendar will be considered as no intake. In the placebo group, all patients will be included regardless of their level of compliance.