Can we use routinely collected primary care medical records to quantify and explain variations in amputation rates across the UK?

Peripheral artery disease (PAD) and diabetes are the two primary risk factors for major lower extremity amputation (MLEA), commonly presenting together. These conditions can result in loss of blood flow to or feeling in the lower limbs causing necrosis, ulceration and infection. Without timely treatment, amputation may be necessary. With both diabetes and vascular disease highly prevalent in the population, monitoring of MLEA incidence is vital to establish performance of preventative measures. Regional variation in MLEA incidence is known to exist within the UK but is unexplained by secondary care health data. Quantifying incidence using primary care health data could aid in this explanation.

This thesis firstly aimed to understand MLEA epidemiology by synthesising existing literature. Then went onto ascertain if MLEAs were well recorded in primary care health data. Next, incidence of MLEA over time in terms of morbidity and region was estimated using linked primary and secondary care data. Finally, this thesis investigated reasons for regional variation.

Differences in methodology and inaccuracies in existing literature were found cause MLEA incidence estimate variation in the UK. Recording of MLEA in primary care data was poor compared to secondary care data; largely due to date discrepancies and re-recording. New investigations found MLEA incidence in England was highest for those with comorbid vascular disease and diabetes. MLEA incidence decreased in all regions over the study period and was highest in the North-East, North-West and South-West of England, the reasons for which were unexplained using these data. Variation between the remaining regions was partially explained by ethnicity distribution.

Regional variation in England remains largely unexplained by primary and secondary care data. Subsequent investigations should explore regional differences in clinical provision and accessibility as the driving reason for regional variation in MLEA incidence rates in England and the UK.