Development of administrative data algorithms to identify patients with critical limb ischemia

Abstract

Administrative data have been used to identify patients with various diseases, yet no prior study has determined the utility of International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM)-based codes to identify CLI patients. CLI cases (n=126), adjudicated by a vascular specialist, were carefully defined and enrolled in a hospital registry. Controls were frequency matched to cases on age, sex and admission date in a 2:1 ratio. ICD-9-CM codes for all patients were extracted. Algorithms were developed using frequency distributions of these codes, risk factors and procedures prevalent in CLI. The sensitivity for each algorithm was calculated and applied within the hospital system to identify CLI patients not included in the registry. Sensitivity ranged from 0.29 to 0.92. An algorithm based on diagnosis and procedure codes exhibited the best overall performance (sensitivity of 0.92). Each algorithm had differing CLI identification characteristics based on patient location. Administrative data can be used to identify CLI patients within a health system. The algorithms, developed from these data, can serve as a tool to facilitate clinical care, research, quality improvement, and population surveillance.

Trends in Major Lower Limb Amputation Related to Peripheral Arterial Disease in Hungary: A Nationwide Study (2004–2012)

“…If CLI specific procedure codes (amputation, revascularization) were added, the sensitivity was even higher (92%). 28 For amputation detection, another publication reported a sensitivity value of 94.4%, 29 which is similar or superior to other disease conditions. 28 As for the comorbidity, the application of disease classification codes (ICD) alone leads to grater uncertainty; 30 therefore, a more complex algorithm of ICD codes for case detection, like the definition of diabetes, was applied.…”

Determinants of Long‐Term Outcomes and Costs in the Management of Critical Limb Ischemia: A Population‐Based Cohort Study

“…Other codes such as 707.14 (ulcer of heel and midfoot) or 785.4 (gangrene), with or without associated procedure codes, could have justifiably been used. However, the addition of procedure codes has been shown to reduce sensitivity and overall agreement when applied to well‐qualified CLI patients 27. Because there are no universally accepted ICD‐9‐CM codes to identify CLI and that the focus of this study was not to determine CLI incidence, but to characterize clinical outcome following diagnosis, a focused list of ICD‐9‐CM codes for CLI diagnosis was used to limit bias introduced by inclusion of cases with unrelated conditions.…”

High-sensitivity cardiac troponin and natriuretic peptide with risk of lower-extremity peripheral artery disease: the Atherosclerosis Risk in Communities (ARIC) Study

“…Based on previous literature, 15,16 clinical PAD in this study was identified based on hospitalizations with the following IInternational Classification of Diseases (ICD)-9 discharge codes: 440.20 (atherosclerosis of native arteries of the extremities, unspecified); 440.21 (atherosclerosis of native arteries of the extremities with intermittent claudication); 440.22 (atherosclerosis of native arteries of the extremities with rest pain); 440.23 (atherosclerosis of native arteries of the extremities with ulceration); 440.24 (atherosclerosis of native arteries of the extremities with gangrene); 440.29 (other atherosclerosis of native arteries of the extremities); 440.3 (atherosclerosis of bypass graft of the extremities); 440.4 (chronic total occlusion of artery of the extremities); 38.18 (endarterectomy, lower limb arteries); 39.25 (aorta-iliac-femoral bypass); 39.29 (other (peripheral) vascular shunt or bypass); and 39.50 (angioplasty or atherectomy of other non-coronary vessel(s)).…”