Diabetes-related amputations on the decline in Singapore

Between 2013 and 2020, lower extremity amputations (LEA) due to diabetes mellitus (DM) showed a downward trend, according to a recent Singapore study. However, other cardiovascular complications, including peripheral arterial disease (PAD) and ischaemic heart disease (IHD), remain prominent public health concerns.

Data for the present analysis were retrieved from the SingHealth Diabetes Registry (SDR), a multi-institutional repository representing around 20 percent of all DM patients in the country. Overall, the study included 222,705 DM patients (48.58 percent women), nearly all of whom had type 2 DM. Only <1 percent had type 1 or other types of diabetes.

In 2013, the SDR database contained data for 92,990 DM patients, increasing to 105,181 by 2015 and to 140,859 in 2020. In general, throughout the observation period, rates of microvascular complications increased across all patient age subgroups. [PLoS One 2022;doi:10.1371/journal.pone.0275920]

The only notable exceptions to this trend were major and minor LEA. In 2013, major LEA occurred at a rate of 19.0 and 21.1 events per 10,000 in patients aged 18–44 and 65–74 years, respectively. By 2020, these had dropped to 4.6 and 15.3 events per 10,000, respectively. The corresponding average annual percent changes (AAPC) were –14.9 (95 percent confidence interval [CI], –23.8 to –4.9) and –5.0 (95 percent CI, –8.0 to –1.8), both of which were statistically significant (p<0.05).

Major LEA in patients aged 45–64 and ≥75 years also showed notable declines in event rate, though the AAPCs did not satisfy statistical significance.

Similar trends were observed for minor LEA. DM patients aged 18–44 and ≥75 years saw a significant decrease in event rate from 2013 to 2020, with AAPCs of –10.2 (95 percent CI, –18.6 to –0.9) and –4.1 (95 percent CI, –7.1 to –1.0; p<0.05 for both), respectively. Declines for those aged 45–64 and 65–74 years were nominal.

Meanwhile, the event rates for peripheral arterial disease (PAD) increased significantly from 2013 to 2020, particularly in patients aged 45–64 (AAPC, 6.1, 95 percent CI, 4.3–8.1), 65–74 (AAPC, 8.2, 95 percent CI, 6.5–10.1), and ≥75 (AAPC, 8.4, 95 percent CI, 6.0–10.9; p<0.05 for all) years.

“We observed decreasing event rates for both major and minor LEAs, suggesting that improvements in major LEAs did not occur because minor LEAs were performed in the clinical setting to prevent major LEAs,” the researchers said, noting that the concomitant increase in PAD rates, which was ascertained through surgical codes for revascularization, could have contributed to the reduced need for LEA.

Nevertheless, definitive reasons behind the decline in amputation remain unknown. “Further research to investigate the pathways to amputation and the role of preventive care measures, pharmacologic strategies, and intervention therapies in the local context are needed to better understand the reasons for the improvement in major and minor LEA rates observed,” they added.

Other micro- and macrovascular complications increased in prevalence over the years, too. These included ischaemic heart disease, diabetic foot and peripheral angiopathy, stroke, diabetic eye complications, nephropathy, and neuropathy. Acute myocardial infarction rates only increased in those aged 18–44 years.

“The comprehensive outcome data and process measures obtained from the SDR has allowed us to generate valuable insights on population health and highlight areas for clinical improvement,” the researchers said. “From a policy perspective, steps must be taken to control the rise in the prevalence of diabetes-related complications and to prevent further strain to the healthcare system.”