Use of health locus of control on self-management and HbA1c in patients with type 2 diabetes.

Participants were assigned by ward rather than random allocation, so differences between wards could have affected results. The study was single-centre and used a quasi-experimental design, limiting generalisation. Self-management and health locus of control were self-reported, and the self-management measure asked about the past seven days, which can introduce memory bias. Follow-up was only 12 weeks, so long-term effects were not assessed. HbA1c was only collected at 12 weeks and participants checked it at a convenient hospital, so the paper does not show that all HbA1c values came from the same testing setting.

Do not conclude that the health locus of control programme alone caused the improvements. Both groups received routine endocrine nursing care, and participants were assigned by ward rather than random allocation, so the added programme's independent effect cannot be separated from routine care, the ward assignment method or time.