Mundinger 2000.

Methods	Randomised trial
Participants	1316 patients (total group), mean age 44.5 years, 25.5% male 7 nurses 17 doctors
Interventions	Intervention: patients allocated to nurse‐led care Control: patients allocated to doctor‐led care Detailed description of the intervention: Compared NPs and doctors as primary care providers within a conventional medical care framework at the same medical centre, where all other elements of care were identical. NPs provided all ambulatory primary care, including 24‐hour call, and made independent decisions for referrals to specialists and hospitalisations. NPs and doctors had the same authority to prescribe, consult, refer, and admit patients. Furthermore, they used the same pool of specialists, in‐patient units, and emergency departments. Supervision, oversight: MD supervision of NPs was consistent with New York State and hospital regulations: In New York State, NPs have a written agreement with an MD that states the MD will meet with the NP once or twice a year to review any practice issues, or to discuss certain cases. No on‐site or regular "supervision" is provided. In terms of hospitals in New York State, and an MD must sign off on every hospital admission within 24 hours of admission, but this still allows an NP with privileges to independently admit and care for a patient.
Outcomes	Patient outcomes: Health status Satisfaction Process of care: Care given by providers Resource utilisation: Consultation rate Use of other services ‐ hospital admissions, emergency department visits, specialty visits
Notes	Country: USA Study period: 2 years Nurse role: first contact and ongoing primary care Nurse title: nurse practitioners Nurse educational background: EQF level 7 Nurse years of experience: average of 8 to 10 years of experience for NPs in the study Nurse additional training: Additional training was received from MDs in hospital‐based activities, including how to admit and bring necessary resources to the patient (specialists, radiology, lab work, etc); training was also provided in interpreting tests and conducting emergency department evaluations.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	No method of randomisation was clearly reported. "Those who provided informed consent were randomly and blindly assigned to either the nurse practitioner or 1 of the physician practices. Different assignment ratios were used during the recruitment period. Initially the ratio was 2:1, with more patients assigned to the nurse practitioner practice, because it opened after the physician practices and was able to accept more new patients. Subsequently, the ratio was changed to 1:1 as the nurse practitioner practice’s patient panel increased".
Allocation concealment (selection bias)	Unclear risk	Method of concealment was not described in sufficient detail.
Baseline characteristics	Low risk	Most baseline characteristics were reported and were similar for both groups. "With regard to demographic characteristics, groups are similar with exception: Significant more patients Medicaid enrolled in physician group (95.7%) versus 87.4% nurse group; p = 0.004".
Baseline outcome measurement	Low risk	Baseline outcomes were reported and were similar for both groups.
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. "Those who provided informed consent were randomly and blindly assigned to either the nurse practitioner or 1 of the physician practices". "Patients were told which provider group they were assigned to after randomisation, and the type of provider could not be masked during the course of care".
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	No information.
Incomplete outcome data (attrition bias) All outcomes	High risk	Follow‐up of patients < 80% (Figure 1, page 64) 1316 were enrolled, 1040 completed 6‐month interview (79%). "Only 406 of the original eligible patients are included, as these patients were the only ones who still received care from original provider". "The number varied per measure from 77 to 119". 77/145 = 53.1%; 119/145 = 82.06%
Selective reporting (reporting bias)	Unclear risk	The protocol was not available.
Contamination	High risk	Contamination could have occurred. "The 159 patients (12.1%) who, after the first visit, either went to a clinic other than the one assigned or to multiple primary care clinics were maintained in the initially assigned group for the analyses, consistent with an intent‐to‐treat analysis. All analyses were repeated without these 159 patients, and the results were the same". Art. Lenz et al: "The present analysis is limited to the 406 patients who received primary care only from the assigned practice and made at least one follow‐up visit to that practice during the 2 years following the initial visit. This subsample was the only one that received the treatment as assigned and in which the effect of the treatment could be isolated".
Bias due to lack of power	Low risk	Sufficient power