Houweling 2011.

Methods	Randomised trial
Participants	239 patients (total group); mean age in intervention group 67.1 (11.0), in control group 69.5 (10.6); 52.9% male in intervention group, 42.3% male in control group 5 doctors (GPs) 2 nurses
Interventions	Intervention: patients with T2DM allocated to nurse practitioners Control: patients with T2DM allocated to GPs Detailed description of the intervention: Compared 2 groups providing diabetes care: Treatment primarily by PNs Standard care from a GP Eligible patients were selected via the GPs’ patient information system and the local pharmacy. Initial selection included patients with a diagnosis of diabetes, patients who were on medication for diabetes, and patients whose glycated haemoglobin (HbA1c) levels had been measured within the past 3 years. Exclusion criteria were (1) no diagnosis of diabetes, (2) type 1 diabetes, (3) diabetes not treated in the primary healthcare setting, (4) inability to participate in the study because of old age or comorbidity, in the opinion of the GP, and (5) not willing to return for follow‐up. PNs were permitted to prescribe 14 different medications and to adjust dosages for a further 30. They were also allowed to order laboratory tests. PNs specifically were not permitted to prescribe insulin but were able to adjust the dosage. Supervision, oversight: PNs worked with a protocol published in "protocollaire diabeteszorg". The protocol indicated when the PN had to consult the GP. In case the patient showed specific complaints during consultation, the patient would be referred to the GP.
Outcomes	Patient outcomes: HbA1c, BP, chol, chol/hdl, glycaemic control Blood pressure Lipid profile HRQOL Diabetes‐related symptoms Patients’ satisfaction Process of care measures: Referred to an ophthalmologist after not having visited one for the past 2 years, by whom measures were taken for feet at‐risk Referred to an internist for starting insulin therapy, after diabetic, antihypertensive, and/or lipid‐lowering drugs had been intensified Resource utilisation: Health care consumption (number of patient visits, number of contacts between PNs and GP)
Notes	Country: Netherlands Study period: unknown Nurse role: ongoing care for patients with diabetes type 2 in a primary care setting Nurse title: practice nurse Nurse educational background: EQF level 5 Nurse years of experience: 2 PNs, experienced in working as a nurse; however no prior experience working in general practice Nurse additional training: At the beginning of the trial, PNs received 1 week of training on a detailed treatment and management protocol aimed at optimising glucose, blood pressure, and lipid profile regulation and eye and foot care in patients with diabetes. Training aimed to educate PNs to a level comparable to the level of a GP, so they would be able to provide diabetes care without supervision.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	A random sequence was used; sequence generation was by odd/even number of closed envelopes. "Patients willing to participate were then randomised by two independent medical investigators (STH and NK)…... Subjects with even numbers were assigned to the intervention group, and those with odd numbers were assigned to the control group".
Allocation concealment (selection bias)	Low risk	Allocation was concealed using sequentially numbered closed envelopes "The patient population was randomised using non‐transparent, closed envelopes containing sequential numbers".
Baseline characteristics	Low risk	Characteristics of patients were similar in both groups. "The groups were comparable with respect to age, gender, T2DM duration, body mass index (BMI), blood pressure, HbA1c and lipid profile".
Baseline outcome measurement	Low risk	Baseline outcomes were reported and were similar for both groups, except feet at‐risk. One of the secondary outcomes was measures to prevent development of diabetic foot symptoms. The percentage of feet at‐risk cases was calculated. Therefore, we do not expect bias due to unsimilarity in baseline feet at‐risk. "The groups were comparable with respect to age, gender, T2DM duration, body mass index (BMI), blood pressure, HbA1c and lipid profile. However, more patients in the PN group had feet at‐risk compared to the GP group".
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	It is unclear whether the outcome was influenced by lack of blinding of patients and care providers.
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Not performed. It is unclear whether the outcome was influenced by lack of blinding of the outcome assessment, because outcomes could not be easily influenced. "The outcome assessors of the clinical variables (such as blood pressure) were not blinded to the intervention".
Incomplete outcome data (attrition bias) All outcomes	Low risk	Follow‐up of patients > 80%
Selective reporting (reporting bias)	Unclear risk	The protocol was not available.
Contamination	Unclear risk	Allocation was by patient. Only 1 practice was involved. Not reported whether trial authors protect against contamination
Bias due to lack of power	Unclear risk	Lack of power, according to the power calculation. If this really was biased, the outcome was unclear. However, trial authors discussed the following: "the required sample size to detect a 0Æ5%‐point difference in HbA1c was a total of 216 patients. Unfortunately, we only have a complete follow‐up of 206 patients. However, the difference in HbA1c ( confidence interval) between groups after 14 months was 0Æ042% (0Æ207;0Æ265). As the confidence interval does not include the possibility of a 0Æ5%‐point difference in HbA1c between groups, we are able to make the conclusions as hypothesised".