Declining number of general practitioners can impair influenza vaccination uptake in Italy

Abstract Background As in many other countries, seasonal influenza vaccination coverage in Italian older adults is insufficient. In Italy, most influenza vaccine doses are administered by general practitioners (GPs), whose number has been declining in recent years. In parallel, the number of patients per GP and consequent GP workload increased dramatically. In this longitudinal study, we aimed to test whether influenza vaccination coverage may be affected by the increased GP workload. Methods The study outcome was the influenza vaccination coverage rate in adults aged ≥ 65 years and registered in 20 Italian regions over the last 23 years. The independent variable of interest was GP workload, proxied as the proportion of GPs with more than 1,500 patients, which is an imposed normative ceiling. By adopting an econometric approach, different specifications of fixed- and random-effects panel regression models were run to assess the association of interest, when adjusted for potential confounders. Results Over the last two decades, most regions showed a negative association between influenza vaccination coverage rates and the density of GPs with a high number of patients. This latter negative association was confirmed (P < 0.05) in different panel model specifications. In particular, in the fully adjusted two-way fixed-effects model, which explained 72.6% of the variance, each 10% increase in the number of GPs with more than 1,500 patients was associated with a 1.7% decrease in influenza vaccination coverage. However, this association was present only in region-years where at least 18% of GPs were deemed overloaded. Conclusions In the upcoming years, the number of Italian GPs is projected to decline further. At the same time, the aging Italian population will determine an even greater workload for GPs. This study demonstrated that increased GP workload may partially explain the spatiotemporal variation in influenza vaccination uptake in the Italian elderly. With the imperative of increasing or at least maintaining influenza vaccination coverage rates, several short- and mid-term initiatives should be implemented in order to optimize GP workload during seasonal immunization campaigns.