Mitigating the hazards of false dichotomies

Editor – The recognition that dichotomising the risk of hyperglycemia into diabetes and prediabetes may render a disservice to patient care¹ has its corollary in the recognition of the continuum of risk of incident atrial fibrillation (AF) associated with hyperglycaemia² or blood pressure.³ The following are pertinent examples of this continuum of risk.

Using data available from electronic medical records collected from the National Taiwan University Hospital, Hsu et al compared 14,309 pairs of patients with prediabetes and normal glucose test results. In that comparison the Kaplan-Meier analysis revealed that the risk of AF was significantly (log-rank P<0.001) greater in patients with prediabetes. Furthermore, the multivariate Cox regression model indicated that prediabetes was independently associated with a significantly increased risk of AF (hazard ratio 1.24, 95% confidence interval 1.11–1.39, P<0.001).²

In their 35-year follow-up study of 2014 apparently healthy men (when evaluated at baseline) in the age range 40–59, Grundvold et al showed that men with baseline systolic blood pressure (SBP) 140 mmHg or more, and those with SBP 128–138 mmHg, had 1.60-fold (95% confidence interval 1.15–2.21) and 1.50-fold (1.10–2.03) risk of atrial fibrillation (AF), respectively.³

These longitudinal studies imply that, over and above the presence of a continuum of cardiovascular risk associated with ‘above threshold’ blood glucose or ‘above threshold’ SBP, the other prognostic operative factor is the duration of exposure to risk factors. Accordingly, the earlier the initiation of measures (including lifestyle interventions) to mitigate AF risk associated with prediabetes or systolic BP >128 mmHg, the greater the probability of mitigating the long-term risk of incident AF and related cardiovascular outcomes. In effect, risk management of AF should not be conditional on a formulation of a conventional diagnosis of diabetes or hypertension.