Trends in morbidity and mortality in patients with diabetes in England

Abstract

Diabetes Mellitus (DM) is a leading public health priority throughout the world. An estimated 463 million adults currently have DM worldwide. People with DM face an increased risk of several macro and microvascular complications and premature mortality. My thesis aims to estimate trends in hospitalisations and mortality in patients with diabetes over the past 20 years in England. Data were extracted from the Clinical Practice Research Datalink, a primary care database, for 628,811 adults from 1998 to 2018 with diagnosed DM. 313,907 of these adults had their primary care records linked to the Office for National Statistics mortality statistics and Hospital Episode Statistics inpatient admissions data. I identified age, sex matched non-DM adults at a ratio of one to one with the DM study population. I used discretised Poisson regression models, adjusted for age, year, DM status and duration, to estimate annual all-cause death and cause-specific death and hospitalisation rates in adults with and without DM over the past 20-years. I also used Logistic regression models to estimate trends in five-year risk of hospitalisation and mortality for sentinel DM complications following diagnosis. All-cause mortality has declined in adults with DM by approximately 30% from 2001-2018. There were mixed trends in cause-specific mortality with large reductions in cardiovascular disease (CVD) mortality alongside more modest declines in other conditions. This led to cancer becoming the leading cause of death in adults with DM. There were mixed trends across cause groupings in hospitalisation rates over a similar period. There were declines in DM-specific aetiological complications including CVD, amputations, and DM itself alongside increases in infections, cancers, and respiratory conditions. During this period, the 5-year risk of hospitalisation for sentinel DM-specific aetiological complications after diagnosis generally declined with the largest reductions in AMI and stroke hospitalisation risk. Changes in the composition of absolute and excess mortality and hospitalisation in adults with DM means that therapeutic, clinical and preventative programmes should be broadened to reflect the diverse set of causes driving persistent excess mortality and morbidity in this patient group.