The association between physician staff numbers and mortality in English hospitals.

Background: Physician medical specialties place specific demands on medical staff. Often patients have multiple co-morbidities, frailty is common, and mortality rates are higher than other specialties such as surgery. The key intervention for patients admitted under physician subspecialties is the care provided on the ward. The current evidence base to inform staffing in physician medical specialty wards is limited. The aim of this analysis is to investigate the association between medical staffing levels within physician medical specialties and mortality.

Methods: This study is a cross-sectional analysis of national data, which is aggregated at provider level. Medical beds per senior, middle grade and junior physicians employed in physician medical specialties were calculated from national employment records for acute hospitals in England, in 2017. Outcome measures included unadjusted mortality rate and Summary Hospital-level Mortality Indicator (SHMI) in physician medical specialties. Both Raw mortality and SHMI include deaths during admission or within 30 days following discharge. Linear regression models were constructed for each medical staffing grade for unadjusted mortality, SHMI and SHMI adjusted for local provider factors.

Findings: The mean number of medical beds per senior, middle grade and junior physicians were 7.3(SD 2.5), 19.7(11.5), 10.1(3.1) respectively. Lower bed numbers per medical staff grade were associated with lower than expected mortality by SHMI; senior(Coefficient 0.012(95%CI:0.005-0.018), = 0.001), middle grade(0.002(0.0002-0.005), = 0.032) and junior(0.008(0.002-0.015), = 0.014). Hospital providers were more likely to achieve a better than expected mortality (SHMI<1) if  beds per physician were lower than; 5.3, 14.6 and 9.0 for senior, middle grade and junior doctors respectively.

Interpretation: Acute hospital providers with fewer beds per medical staff of all grades are associated with lower than expected mortality.

Funding: No external funding is associated with this analysis.