The incidence of and risk factors for hospitalisations and amputations for people with diabetes-related foot ulcers in Queensland, 2011–19: an observational cohort study

Objectives

To assess the incidence, risk factors, and length of stay for hospitalisations, with and without amputations, of people with diabetes-related foot ulcers (DFU).

Study design

Prospective observational cohort study; secondary analysis of linked Diabetic Foot Services and Queensland Hospital Admitted Patient Data Collection data.

Settings, participants

All people with DFU who visited any of 65 outpatient Diabetic Foot Service clinics in Queensland for the first time during 1 July 2011 – 31 December 2017, followed until first DFU-related hospitalisation, ulcer healing, or death, censored at 24 months.

Main outcome measures

First overnight hospitalisations for which the principal diagnosis was DFU-related (International Statistical Classification of Diseases, tenth revision, Australian modification; Australian Classification of Health Interventions codes), by amputation procedure type (none, minor [distal to ankle], major [proximal to ankle]).

Results

Among 4709 people with DFU (median age, 63 years (interquartile range [IQR], 54–72 years); 3275 men [69.5%]; type 2 diabetes, 4284 [91.0%]), DFU-related hospitalisations were recorded for 977 people (20.7%): 669 without amputations (68.5%), 258 with minor amputations (26.4%), and 50 with major amputations (5.1%). The incidence of first DFU-related hospitalisations was 50.8 (95% confidence interval [CI], 47.7–54.1) per 100 person-years lived with DFU before healing, death, or loss to follow-up. The incidence of first DFU-related hospitalisation with no amputation was 39.0 (95% CI, 36.2–42.1), with minor amputation 18.0 (95% CI, 17.0–20.0), and with major amputation 5.3 (95% CI, 4.4–6.3) per 100 person-years with DFU. The median length of stay for DFU-related hospitalisations was six (IQR, 3–12) days with no amputations, ten (IQR, 5–19) days with minor amputations, and 19 (IQR, 11–38) days with major amputations. The risks of all DFU-related hospitalisation outcomes were higher for people with deep ulcers or severe peripheral artery disease. The risks of DFU-related hospitalisation with no amputations were also greater for people aged 37–59 years than for those aged 60 years, and for people with cardiovascular disease, infections, or previous amputations; with minor amputations for people who smoked, had end-stage renal disease, previous amputations, moderate to severe infections, or peripheral artery disease, or who were not receiving knee-high offloading or DFU debridement treatments; and with major amputations for people with end-stage renal disease, peripheral artery disease, or larger ulcers.

Conclusions

The incidence of DFU-related hospitalisations among people with DFU was high, and most did not involve amputations. Risk factor profiles differed between hospitalisations with or without amputation procedures. Our findings could assist services determine which people with DFU would benefit most from intensive interventions, potentially averting large numbers of diabetes-related hospitalisations.