In this cross-sectional survey of GPs in Vaud, Switzerland, the vast majority of participants was engaged in one or more complementary activities and spent a considerable amount of time on these tasks. The primary predictor of participating in complementary activities, beyond working more hours per week on standard consultations, was practicing in a rural area, where other health care providers may be hard to reach .
As the shortage of GPs in Switzerland is predicted to be greatest rural areas , not only do these areas face a drop in the provision of basic medical services, but also potentially in diverse fields of health care delivery such as in-office teaching, nursing home care and other community activities. One possibility is that rural physicians participate in more complementary activities in order to increase their income. However, a study in Germany, which has a similar health-care system as Switzerland, showed nearly equal incomes of rural and urban GPs through standard in-office care, measured on the number of private insured patients . Thus, remuneration of the complementary activities seems unlikely to be a major motivator.
In the current study, GPs reported spending an average of 19 min daily on teaching and 20 min in specific external structures (e.g. nursing homes), each corresponding to an average in-office consultation in Switzerland . This is more than Gottschalk et al. reported for the USA in 2005 (13 and 5 min respectively)  but similar to findings from Granja et al. for Portugal in 2015 (15 min spent on teaching on average per day) , indicating that these health care areas may be relying more on GPs engagement over time. An increase in time spent on complementary activities would support Cohidon et al., who compared a more limited number of activities between 1993 and 2012 using a nation-wide sample of Swiss GPs and observed an increase from 28 to 66% of GPs involved in paid activities beyond their standard functions . As in general, GPs tend to spend only about half their time on direct in-office patient contact , it is clear that out-of-practice medical services are taking an important role in their working days .
Given the number and variety of community roles filled by GPs, the new generation of medical professionals who value an equilibrated work-life balance and lighter weekly workload  may not be able to cover all needs. On the other hand, as complementary activities seem to strengthen the attractiveness of primary care [18, 19], GPs may favour complementary activities at the expense of in-office consultations. Regardless, the augmenting implication of GPs in these complementary activities can be explained either by an augmented need for GPs in out-of-practice medical care delivery or by the wish of primary physicians for a broader spectrum of work tasks.
Women appear to participate in fewer activities in univariate analyses (IRR 0.66 (95% CI 0.51–0.86)), however this result is no longer statistically significant when accounting for other physician and practice characteristics. This may be due to the observation that women in our study were younger than participating men, as age was significantly associated with more involvement in complementary activities. In the USA, spending more hours per week on standard consultations and working in a rural area were both independently associated with higher rates of participating in volunteer activities .
Strengths and limitations
We had a relatively small sample size with a low response rate. As the study is based on self-reported data, possible declaration bias including recall bias cannot be excluded. Declaration bias including recall bias could result in GPs over- or underestimating their complementary engagement. As we are investigating the association between physician variables and engagement in complementary activities, differential recall bias seems unlikely to explain our primary results of an association between greater involvement and working in rural areas. Given our broad definition of complementary activities, it may not be surprising that most GPs are involved in at least one activity. Enabling participation through paper form during continuing medical education courses in addition to an online survey allowed us to achieve a more diverse sample, as GPs who filled out the paper form reported fewer complementary activities than GPs answering online. Further, while we asked about remuneration, GPs did not specify the exact amount. Important discrepancies between financial incentives perceived in the different categories could not be detected through this study. Our study shows interesting trends, but is from only one sample and should be confirmed using similar definitions in other settings.