Evaluation of a theory-based nutrition intervention for older adults with diabetes mellitus

Objective To evaluate an intervention to improve food label knowledge and skills in diabetes management among older adults with diabetes mellitus. Design A randomized pretest-posttest control group design was used. Subjects/setting Participants (48 experimental, 50 control) were aged 65 years and older with type 2 diabetes for 1 year or longer; 93 participants (95%) completed the study, conducted in an outpatient setting. Intervention The intervention included 10 weekly group sessions led by a dietitian. Information processing, learning theory, and Social Cognitive Theory principles were used in program development and evaluation. Main outcome measures participants' knowledge, outcome expectations (expected results of behavior), self-efficacy, and decision-making skills were assessed, Instrument validity and reliability were established before program evaluation. Statistical analyses performed Factor analysis identified underlying factor structures. Analysis of covariance with pretest score as covariate was used to compare groups at posttest. Paired t tests compared results within groups. Results Two factors were identified for outcome expectations (positive and negative) and for self-efficacy (promoters of and barriers to diabetes management.). The experimental group had greater improvement in total knowledge scores (mean standard error of the mean: 7.8+/-0.7) than the control group (0.2+/-0.7) (P<.0001), positive outcome expectations (0.59±0.15 vs 0.06±0.15, P=.01), promoters of diabetes management (0.83±0.12 vs -0.09±0.18, P≤.001) and decision-making skills (5.1±0.5 vs 0.3±0.5, P<.0001) and greater reduction in barriers to diabetes management (1.1+/-0.16 vs 0.34+/-0.16, P<.01). No significant difference in negative outcome expectations occurred between groups at posttest. Applications/conclusions; Older adults with diabetes can benefit from nutrition education designed to improve knowledge and skills necessary for diabetes management.