Reliability of Patient reporting of Pan-retinal Photocoagulation (PRP) Compared to Fundus Photograph Assessment in Sixteen Years of the Epidemiology of Diabetes Interventions and Complications Study (EDIC)

Abstract

 

Purpose:

 

To determine the reliability of patient reporting of prior PRP among 1317 type 1 diabetic participants over sixteen years in the EDIC study.

 

Methods:

 

At the annual visit, patients were asked by EDIC staff whether they had PRP since the last completed annual clinic visit. Fundus photographs were collected in one quarter of the cohort each year and in the whole cohort at EDIC years 4 and 10. Photographs were graded centrally for presence and extent of PRP scars. Sixteen years of patient reporting and photograph grading of PRP were compared in 1317 EDIC participants. Discrepant cases were adjudicated by a senior grader.

 

Results:

 

Among 1312 with valid photos (5 excluded: 1 had un-gradable photo and 4 had questionable laser), 1263(96%) patients accurately reported history of PRP using adjudicated photograph grading as the gold standard. Sensitivity was 91%, specificity 97%, positive predictive value 75%, negative predictive value 99%, and kappa was 0.80. There were 60 discrepant assessments between patient report and original photograph grading without adjudication. Photographs of these 60 patients were reviewed. In 4 (7%), the original photo grading was in error (2 false negatives (FN) and 2 false positives (FP) due to other scar present). Forty-seven (80%) of the discrepancies were due to patient mis-report including 11 FN and 36 FP. Of the latter, 16 reported having PRP but had focal photocoagulation scar for macular edema. The remaining 9 (13%) were due to questionable, un-gradable photos or other reasons.

 

Conclusions:

 

The high sensitivity and specificity of patient reporting of PRP validated it as a useful tool in assessing PRP for diabetic retinopathy in the absence of a clinical exam. However, the lower positive predictive rate limits the use of patient report as a surrogate for PRP.  

 

Clinical Trial:

 

http://www.clinicaltrials.gov NCT00360893

 

Keywords: diabetic retinopathy • reading • clinical (human) or epidemiologic studies: treatment/prevention assessment/controlled clinical trials