Research activity and the association with mortality

Abstract

Introduction: The aims of this study were to describe the key features of acute NHS Trusts with different levels of research activity and to investigate associations between research activity and clinical outcomes.

Methods: National Institute for Health Research (NIHR) Comprehensive Clinical Research Network (CCRN) funding and number of patients recruited to NIHR Clinical Research Network (CRN) portfolio studies for each NHS Trusts were used as markers of research activity. Patient-level data for adult non-elective admissions were extracted from the English Hospital Episode Statistics (2005-10). Risk-adjusted mortality associations between Trust structures, research activity and, clinical outcomes were investigated.

Results: Low mortality Trusts received greater levels of funding and recruited more patients adjusted for size of Trust (n = 35, 2,349 £/bed [95% CI 1,855-2,843], 5.9 patients/bed [2.7-9.0]) than Trusts with expected (n = 63, 1,110 £/bed, [864-1,357] p<0.0001, 2.6 patients/bed [1.7-3.5] p<0.0169) or, high (n = 42, 930 £/bed [683-1,177] p = 0.0001, 1.8 patients/bed [1.4-2.1] p<0.0005) mortality rates. The most research active Trusts were those with more doctors, nurses, critical care beds, operating theatres and, made greater use of radiology. Multifactorial analysis demonstrated better survival in the top funding and patient recruitment tertiles (lowest vs. highest (odds ratio & 95% CI: funding 1.050 [1.033-1.068] p<0.0001, recruitment 1.069 [1.052-1.086] p<0.0001), middle vs. highest (funding 1.040 [1.024-1.055] p<0.0001, recruitment 1.085 [1.070-1.100] p<0.0001).

Conclusions: Research active Trusts appear to have key differences in composition than less research active Trusts. Research active Trusts had lower risk-adjusted mortality for acute admissions, which persisted after adjustment for staffing and other structural factors.

Fig 1. NIHR CCRN funding (£/bed) in English acute NHS Trusts with Trusts sub-grouped as low (n = 35), as expected (n = 63) and, high (n = 42) mortality.

For each group, the mean and 95% CI funding are shown. The low mortality Trusts had significantly higher levels of CCRN funding than the as expected (p<0.0001) or high (p = 0.0001) mortality Trusts.

Fig 2. Risk adjusted odds ratio of inpatient death in English NHS Trusts by tertile of scaled CCRN funding.

The analysis is restricted to standard resource trusts. For each group, the mean and 95% CI are shown. Trusts in the lowest and middle funding tertile had significantly higher mortality relative to the highest funded trusts.

Fig 3. Risk adjusted odds ratio of inpatient death in English NHS Trusts by tertile of scaled CCRN funding.

The analysis is restricted to higher resource trusts. For each group, the mean and 95% CI are shown. Trusts in the lowest funding tertile had significantly higher mortality relative to the highest funded trusts.