Descriptions of interventions, impact on the 4Cs, and their effects on outcomes
The characteristics of the intervention programmes or sets of innovation features described in the articles varied widely, but it was possible for the authors to group the vast majority of innovations into 18 distinct (and one non-distinct) categories (Table 2).
Table 2. Primary care innovation categories and definitions
The number of intervention categories explored in the included articles are presented in Figure 3. The most commonly studied types of innovations were those aimed at improving access (explored in 21 articles), followed by payment-based enhancements (in 18 articles), and innovations implementing team-based care or technology enhancements (each in 14 different articles). Conversely, innovations related to pharmacy/medication improvements, those trying to enhance coordination or information exchange, and those aimed at increasing the control over workload were studied in five, four, and one article respectively (Supplementary Table 2a–d).
Figure 3. Number of innovation categories included in studies. Categories are not mutually exclusive.
The innovation categories explored in each of the included articles are outlined in Supplementary Tables S2a–d, with detailed descriptions of the innovations and the numerical magnitudes of their effects on the corresponding quadruple-aim outcome(s), given in Supplementary Table S4. The 4C that was most consistently aimed at to be improved was comprehensiveness — this featured in 34 of the 37 articles. Next in line came the interventions that aimed to have a positive impact on continuity (28 articles), first contact (23 articles), and coordination (20 articles). The description of the general direction of the effects of the innovations is presented, organised by the number of ‘Cs’ on which the studies had an impact (Supplementary Tables S2a–d and Supplementary Table S3).
Thirty-five per cent (13/37)17–29 of the interventions/programmes impacted all of the 4Cs (Supplementary Table S2a). These programmes included, on average, 7.25 intervention categories each (median = 7), and the most recurrently explored outcome was healthcare costs and utilisation (which featured in 10 of the 13 articles), followed by population health outcomes (in five of the 13 articles). Patient satisfaction was reported in four of these interventions, and one looked at provider satisfaction.
Programmes impacting on all of the 4Cs showed mixed results in almost all of their reported outcomes (Supplementary Table S2a). For utilisation, some parameters improved (increased screening and preventive services, increased visits to primary care relative to specialists) while, for other parameters, there were statistically significant and non-significant reductions in emergency department (ED) visits, outpatient visits, and hospitalisations. For expenditures, some studies reported cost savings and decreased costs, others reported no significant changes, and one study reported significant increases in costs for coverage of prescriptions.
For population health outcomes, though statistically significant improvements were reported for chronic illness care, patients with cardiovascular disease, control of diabetes, and the reduction in diabetes complications, there were also non-statistically significant changes for some diabetes parameters, control in patients with chronic obstructive pulmonary disease and asthma, vascular complications, and mental health. Two of the four interventions reporting on patient satisfaction found statistically significant improvements for perception of GPs’ work, while the other two reported mixed results for perceived quality and coordination of services, and no differences for access to care, same-day appointments, and satisfaction with primary care. The study looking at provider satisfaction also reported mixed results (significant increase in satisfaction for communication with patient and management of chronic care; no differences for overall satisfaction, knowledge of patients, and care coordination).
Nineteen per cent (seven out of 37) of the innovation programmes aimed to have an impact on three of the 4Cs (Supplementary Table S2b). These programmes averaged 5.6 intervention categories each (median = 6); six of seven studies explored healthcare costs and utilisation, and four of seven studies looked at population health outcomes. None explored patient or provider satisfaction.
The three programmes impacting on first contact, comprehensiveness, and continuity30–32 showed mixed results for population health (improvements for patients reaching low-density lipoprotein target levels; non-significant changes for quality-of-life scores) and utilisation outcomes (increased primary care annual services and visits; specialty visits remained the same, but the proportion of patients readmitted, along with the number of readmissions and hospital days, increased).
The two interventions that impacted comprehensiveness, continuity, and coordination33,34 also reported mixed results: these included a statistically significant lower risk of death, but non-statistically significant changes in health status and, for utilisation outcomes, a decrease in the number of specialist visits, but non-significant changes for hospital use and Medicare payments.
The study that impacted first contact, continuity, and coordination35 reported statistically significant increases in non-urgent primary care visits, but mixed results for hospital admission and length of stay, and a statistically significantly increased number of prescriptions. The study that impacted first contact, comprehensiveness, and coordination36 reported statistically significant improvements for diastolic blood pressure and microalbumin:creatinine ratio tests, but no significant changes for haemoglobin A1c, lipid measures, and the number of tests and ED/hospital visits.
Forty-one per cent (15 out of 37) of the innovation programmes impacted two of the 4Cs (Supplementary Table S2c). These programmes included an average of 4.1 intervention categories each (median = 4), and reported mostly on healthcare costs and utilisation outcomes (12 of 15 studies), followed by population health outcomes (five of the 15 studies). Two reported patient satisfaction outcomes and two provider satisfaction.
For the seven studies that impacted on comprehensiveness and continuity,37–43 there were mixed results for: population health outcomes (significant improvements in several diabetes measures, blood pressure control, and smoking status; no differences for other diabetes-related measures and cardiovascular health) and utilisation outcomes (improvements for screening services and more services provided, especially in capitation-based models; non-statistically significant changes for continuity of care, ED use, and several documentation parameters).
There were improvements in satisfaction for providers whose payment model factored in panel size. The three studies that impacted comprehensiveness and coordination44–46 reported: improvements in older populations for depression and dyspnoea, but no changes for other behavioural disorders, pain and falls; improvements for unplanned hospitalisations and increased preventive measures, and cost avoidance and decreased service utilisation for chronic conditions in incentive-based services. There were no changes in total hospital admissions, and increased costs for incentive-based diabetes services.
The three studies that focused on first contact and comprehensiveness47–49 reported mixed results for healthcare costs and utilisation — namely, statistically significant decreases in Medicare expenditures, per-member and per-quarter costs, and decreased primary care visits and visits per full-time equivalent, but no changes for hospitalisations, ED visits, and other utilisation outcomes. These studies reported statistically significant improvements for some patient satisfaction outcomes (timely appointments and self-management support, satisfaction with ability to see personal doctor, ease of getting care, and ratings of health care) but not for others (communication with providers, or knowledge of providers of other services). For providers, there was improved perception towards quality and services provided.
The two studies that impacted first contact and continuity50,51 reported mixed results for healthcare costs and utilisation outcomes (reduction of avoidable long-term ED visits, decreases in cost of drug prescriptions, increased GP consultations, and decreased specialist consultations, among others; increased costs of GP and specialist consultations, and no changes of ED hospitalisations).
Only two interventions52,53 impacted on just one of the 4Cs (comprehensiveness) (Supplementary Table S2d). These had one and two intervention categories, and reported mixed results for population health (some improvements in BP control for some patient groups but not for others) and resource utilisation outcomes (reductions for specialty care visits but non-statistically significant effects on proportion of patients seeing multiple doctors or surgical admissions).