Diagnostic accuracy of existing methods for identifying diabetic foot ulcers from inpatient and outpatient datasets

Abstract

BackgroundAs the number of persons with diabetes is projected to double in the next 25 years in the US, an accurate method of identifying diabetic foot ulcers in population-based data sources are ever more important for disease surveillance and public health purposes. The objectives of this study are to evaluate the accuracy of existing methods and to propose a new method.MethodsFour existing methods were used to identify all patients diagnosed with a foot ulcer in a Department of Veterans Affairs (VA) hospital from the inpatient and outpatient datasets for 2003. Their electronic medical records were reviewed to verify whether the medical records positively indicate presence of a diabetic foot ulcer in diagnoses, medical assessments, or consults. For each method, five measures of accuracy and agreement were evaluated using data from medical records as the gold standard.ResultsOur medical record reviews show that all methods had sensitivity > 92% but their specificity varied substantially between 74% and 91%. A method used in Harrington et al. (2004) was the most accurate with 94% sensitivity and 91% specificity and produced an annual prevalence of 3.3% among VA users with diabetes nationwide. A new and simpler method consisting of two codes (707.1× and 707.9) shows an equally good accuracy with 93% sensitivity and 91% specificity and 3.1% prevalence.ConclusionsOur results indicate that the Harrington and New methods are highly comparable and accurate. We recommend the Harrington method for its accuracy and the New method for its simplicity and comparable accuracy.

Systolic blood pressure variability and lower extremity amputation in a non-elderly population with diabetes

“…Second, diseases and amputations were identified from administrative data using ICD-9-CM and CPT-4 codes and the accuracy of disease coding may have affected our results. Even though our previous study indicates that some conditions such as foot ulcers can be determined with very high accuracy from the VA administrative data (32), we especially recognize that non-symptomatic PVDs may have been under-identified in our data. Third, we did not have access to some factors that may have affected both the SBP variability and the risk of amputation such as smoking and physical activity.…”

Burden of Diabetic Foot Ulcers for Medicare and Private Insurers

“…Patients were then divided into two mutually exclusive cohorts based on the presence of at least one foot ulcer diagnosis occurring after a diabetes diagnosis during a recent time period (i.e., January 2007-December 2010 for Medicare and January 2007-September 2011 for private insurance) identified using ICD-9-CM codes 707.1x, 707.8x, and 707.9x, consistent with prior claims-based analyses of DFU (9,10,12).…”

Increasing SBP variability is associated with an increased risk of developing incident diabetic foot ulcers

“…We defined cases as those individuals in the cohort who were diagnosed with an incident diabetic foot ulcer during the 5-year follow-up period [20,21]. The cohort run-in period allowed us to identify incident, rather than prevalent, foot ulcers.…”

“…The cohort run-in period allowed us to identify incident, rather than prevalent, foot ulcers. Foot ulceration was identified using validated ICD-9-CM codes present in in-patient and out-patient datasets ( n = 85 086) [21]. For patients with multiple foot ulcerations, either because of recurrence or development on the contralateral foot, we used the first diagnosis only.…”