Longitudinal clinical trajectory analysis of individuals before and
after diagnosis of Type 2 Diabetes Mellitus (T2DM) indicates that
vascular problems start early
Abstract
Introduction Type 2 diabetes mellitus (T2DM) frequently associates with
increasing multi-morbidity/treatment complexity. Some headway has been
made to identify genetic and non-genetic risk factors for T2DM. However
longitudinal clinical histories of individuals both before and after
diagnosis of T2DM are likely to provide additional insight into both
diabetes aetiology/further complex trajectory of multi-morbidity.
Methods This study utilised diabetes patients/controls enrolled in the
DARE (Diabetes Alliance for Research in England) study where pre- and
post-T2DM diagnosis longitudinal data was available for trajectory
analysis. Longitudinal data of 281 individuals (T2DM n=237 vs matched
non-T2DM controls n=44) were extracted, checked for errors and logical
inconsistencies and then subjected to Trajectory Analysis over a period
of up to 70 years based on calculations of the proportions of most
prominent clinical conditions for each year. Results For individuals who
eventually had a diagnosis of T2DM made, a number of clinical phenotypes
were seen to increase consistently in the years leading up to diagnosis
of T2DM. Of these documented phenotypes, the most striking were
diagnosed hypertension (more than in the control group) and asthma. This
trajectory over time was much less dramatic in the matched control
group. Immediately prior to T2DM diagnosis a greater indication of
ischaemic heart disease proportions was observed. Post-T2DM diagnosis,
the proportions of T2DM patients exhibiting hypertension and infection
continued to climb rapidly before plateauing. Ischaemic heart disease
continued to increase in this group as well as retinopathy, impaired
renal function and heart failure. Conclusion These observations provide
an intriguing and novel insight into the onset and natural progression
of T2DM. They suggest an early phase of potentially-related disease
activity well before any clinical diagnosis of diabetes is made. Further
studies on a larger cohort of DARE patients are underway to explore the
utility of establishing predictive risk scores.