The aim of the COR-PRIM study was to demonstrate the superiority of patient PBL over home-sent patient information for evaluating long-term effects of PE and self-care in patients with CHD.
Trial design
The COR-PRIM study was a prospective, randomised, parallel, and single centre study (NCT01462799) involving 157 patients with CHD in a primary care setting in south-eastern Sweden. The COR-PRIM study tested the hypothesis that one year of PBL patient education improves a patients’ self-efficacy, and PE to change self-care significantly compared to one year of standardised home-sent patient information. Recruitment began in November 2011 and tests were performed at baseline[15] and one, three, and five years, which is still ongoing, after completion of a one-year PBL programme for patients with CHD. Here, we report only data from baseline and one-year follow-up, which was finally collected in 2015.
Patients
According to the COR-PRIM study,[14] the following inclusion criteria were used: (i) CHD verified by MI and/or Percutaneous Coronary Intervention (PCI) and/or coronary artery by-pass surgery (CABG) within 12 months before planned start of the intervention irrespective of age; (ii) stable cardiac condition; (iii) optimised cardiac medication not substantially changed the previous month; and (iv) completed hospital heart school at one of the identified six primary health care centres (PHCS). The following exclusion criteria were used: (i) planned CABG or other conditions demanding continuing cardiologic care such as on-going contact with heart failure clinic; (ii) life-expectancy ≤ 1 year; (iii) documented psychiatric disease impeding cooperation with other people; (iv) obvious abuse of alcohol or narcotics; and (v) inability to read or communicate in Swedish.
Randomisation and procedures
During a follow-up at hospital, nurses informed patients about the study and those patients who agreed to receive further information were contacted by the principal researcher by letter and telephone. Some patients voluntarily stated their reasons for not participating in the study – e.g., difficulties leaving work/home; long distance to the PHCS; and disapproval of group activity.
The patients who agreed to participate, returned informed consent document and who had completed the baseline questionnaires were randomised (1:1 ratio) to either the experimental group (received PBL) or the control group (received patient information leaflets delivered to the home address) before any intervention. The randomisation was carried out with sealed unmarked opaque envelopes and were assigned by an administrator in a room separated from the research and intervention area. We used a block of 18 study numbers that were blindly allocated to either PBL or home-sent patient information[16]. The envelopes contained a unique number from 1 to 185 that were hand-picked by an administrator who was blinded during this procedure.
Conventional care and interventions
All patients were offered a brief conventional CRP at an outpatient clinic in hospital care that included counselling visits with a nurse and a cardiologist, physical exercise, diet counselling, and a day long heart school. The conventional care provided and the design of the interventions described below and in a previous paper[14]. Here, we provide a short description of the interventions.
Home-sent patient information group
The patients in the home-sent patient information group served as controls. They met directly after randomisation in the PHCS to discuss self-care goals and follow-ups during the study year. Predetermined written patient information was provided[17] to support self-care as suggested in brochures produced, for example, by The Swedish Heart and Lung Foundation. Next, the patient information was mailed to the patient’s home address during the study year.
PBL intervention group
The patients in the experimental group (6-9 patients/group) started the one-year PBL intervention (13 occasions; two hours/occasion) at a PHCS. The goal was to improve self-care by strengthening patient PE with a focus on understanding cardiac symptoms, medications, and the health benefits associated with lifestyle changes regarding diet, physical activity, and mental health. Nurses who were trained to tutor the patients in the PBL process[18] helped patients formulate issues and self-care goals. Resource professionals (e.g., physician and dietician) and relatives were invited to the groups. For further descriptions, see Kärner et al[14].
Outcomes
The primary outcome was for PE to reach self-care goals one year after randomisation. The questionnaires used to assess the primary and secondary outcomes are briefly presented here and more thoroughly elsewhere[15]. PE was assessed using the SWE-CES-10 questionnaire, which was developed to survey PE in patients with CHD. SWE-CES-10, based on SWE-DES-23, is a valid and reliable tool for assessing PE in patients with diabetes mellitus[19-21]. SWE-DES-10, a shortened version of SWE-DES-23, was also found to be reliable. After securing approval from the author of the scale, we replaced the word ‘diabetes’ with ‘heart disease’. The SWE-CES-10 has four subscales: 1) Goal achievement and overcoming barriers to goal achievement; 2) Self-awareness; 3) Managing stress; and 4) Assessing dissatisfaction and readiness to change. The items are scored on a five-point Likert scale ranging from strongly agree (1) to strongly disagree (5). A higher value means a stronger PE[22]. Secondary outcomes were self-efficacy in general,[23] healthy diet,[24] and physical exercise[25, 26].Self-efficacy was assessed using the General Self-efficacy Scale (GSES), which uses a four-point Likert scale ranging from not at all true (1) to exactly true (4). A higher score indicates a higher GSES. GSES has been confirmed to be highly reliable, stable, and valid[27, 28]. Healthy diet was assessed using the Nutrition Self-efficacy Scale (NSES) and physical exercise using the Physical Exercise Self-efficacy Scale (PSES), both which use a four-point Likert scale ranging from very uncertain (1) to very certain (4). NSES and PSES are assessed to be reliable and valid tools[24]. Physical exercise was also assessed using Stages of Change Scale[25]Well-being[29] was assessed using the Cantril Ladder of Life, used in large populations and tested for reliability and validity,[30] and the EQ5D,[31] a reliable and valid tool for use in patients with CHD. Blood pressure, BMI, waist size, and blood tests were used at follow-up to measure effects of self-care. Primary and all secondary outcome data were included in the intention-to-treat (ITT) analysis.
Statistical analysis
Sample size justification
Sample size calculation was based on the estimation that patients with diabetes mellitus, also a life-long disease, who reported poor self-rated health scored three on several subscales of the SWE-DES[21] and around 0.6 above three for those reporting good self-rated health, α = 0.05 and 1-β = 0.80[21]. Accordingly, at least 63 patients were needed in each group, so we recruited 157 patients to compensate for withdrawals.
Primary analysis: intention-to-treat
Intention-to-treat included patients who fulfilled all inclusion criteria. Missing values in the primary outcome SWE-CES-10 have been substituted by the typical mean for the sample.
Continuous data are presented as means +SD or as median and IQR. Between-group differences were tested using independent-sample Student’s t-test for numerical variables or Mann-Whitney U test for non-normal distributed variables. For categorical variables, Fisher’s exact test was used. All statistical tests were two-sided with a significant level of P ≤ 0.05. The data were analysed using SPSS (IBM® SPSS Statistics, Version 23).