Unravelling the determinants of medical practice variation in referrals among primary care physicians: insights from a retrospective cohort study in Southern Israel

Objectives Reducing medical practice variation (MPV) is a central theme of system improvement because it is associated with poor health outcomes, increased costs and disparities in care. This study aimed to estimate the extent to which each determinant (patient, physician, clinic) explains MPV among primary care physicians and to identify the characteristics of health services with a greater explained variance.Methods A retrospective cohort study of primary care physicians practising in non-private clinics of Clalit Health Services in Southern Israel, for longer than a year between 2011 and 2017 and with more than 100 adult patients per practice. We assessed the variation in referral rates among 17 health services and the proportion explained by each domain (patient, physician and clinic). We used generalised linear negative binomial mixed models and the Nakagawa’s R2, computing the marginal r2.Results The study included 243 physicians working in 295 practices and 139 clinics. The mean-explained variance was 28.5%±10.0%, where physician characteristics explained 4.5% of the variation. The intrapractice variation (within a single physician between the years) was explained better than the interphysician (between physicians). Health services with high explained variation were blood tests characterised by both low intrapractice variation (Rs=−0.65, p value=0.005) and high referral rates (Rs=0.46, p value=0.06).Conclusion Over 70% of MPV is not explained by the patient, clinic and physician demographic and professional characteristics. Future research should focus on the fraction of MPV that is explained by the physicians’ psychological characteristics, and thus potentially identify psychological targets for behavioural modifications aimed at reducing MPV

Temperature and preeclampsia: Epidemiological evidence that perturbation in maternal heat homeostasis affects pregnancy outcome.

INTRODUCTION:This study aims to determine the association between temperature and preeclampsia and whether it is affected by seasonality and rural/urban lifestyle. METHODS:This cohort study included women who delivered at our medical center from 2004 to 2013 (31,101 women, 64,566 deliveries). Temperature values were obtained from a spatiotemporally resolved estimation model performing predictions at a 1×1km spatial resolution. In "Warm" pregnancies >50% of gestation occurred during the spring-summer period. In cold pregnancies >50% of gestation occurred during the fall and winter. Generalized estimating equation multivariable models were used to estimate the association between temperature and incidence of preeclampsia. RESULTS:1) The incidence of preeclampsia in at least one pregnancy was 7% (2173/64,566); 2) during "warm" pregnancies, an elevation of one IQR of the average temperature in the 1st or the 3rd trimesters was associated with an increased risk to develop preeclampsia [patients with Jewish ethnicity: 1st trimester: relative risk (RR) of 2.38(95%CI 1.50; 3.80), 3rd trimester 1.94(95%CI 1.34;2.81); Bedouins: 1st trimester: RR = 2.91(95%CI 1.98;4.28), 3rd trimester: RR = 2.37(95%CI 1.75;3.20)]; 3) In "cold" pregnancies, an elevation of one IQR of average temperature was associated with a lower risk to develop preeclampsia among patients with Bedouin-Arab ethnicity RR = 0.68 (95% CI 0.49-0.94) for 1st trimester and RR = 0.62 (95% CI 0.44-0.87) for 3rd trimester. CONCLUSIONS:1) Elevated averaged temperature during the 1st or 3rd trimesters in "warm" pregnancies confer an increased risk for the development of preeclampsia, especially in nomadic patients; 2) Of interest, during cold pregnancies, elevated averaged temperature was associated with a lower risk to develop preeclampsia for nomadic patients. 3) These findings suggest temperature might be associated with perturbations in maternal heat homeostasis resulting in reallocation of energy resources and their availability to the fetus that may increase the risk for preeclampsia. This observation is especially relevant in the context of global warming and its effects on maternal/fetal reproductive health