Medical app for supporting gout diagnosing without the need of microscopic investigation by a rheumatologist.
Doctors diagnose gout most of the time by clinical judgment or experience. This may imply risk of false diagnosis and, subsequently, wrong or delayed management. To meet this problem Hein Janssens, general practitioner in Lobith-Tolkamer and senior investigator at the department of Primary and Community Care devised and developed an app in cooperation with Joshua Steinberg, family physician in Binghamton (NY) and clinical assistant professor of Family Medicine with the Upstate Medical University, Syracuse (NY), US.
Gold standard diagnosis can be made with certainty by polarized light microscopy identifying specific crystals in joint fluid aspirated from the painful gout joint (by a rheumatologist). However, it is impractical to make diagnoses always in this way (gout prevalence 2-3%!), because polarized light microscopy is not easily available everywhere, particularly not in primary care, where 90% of gout patients are managed. Therefore, a valid alternative like the current app supporting clinical decision making is very welcome.
After checking presence of patient characteristics like joint redness, involvement of the big toe basic joint, hypertension or a cardiovascular disease, and a serum uric acid level >0.35mmol/L the app calculates (based on a validated decision rule) likelihood score for having gout and presents three score ranges (≤4 diagnosis ‘very unlikely’; ≥8 ‘highly likely’; between 4 and 8 ‘indeterminate’) including interpretations. It provides also educational background information (about gout, gout diagnosis, and the original decision rule) and internet links to referenced scientific articles.
Though the app decision rule is based on data of 381 primary care patients, it has also been validated for patients in secondary care. If rheumatologists are not available for synovial fluid analysis, the app can be used too, e.g. at the emergency department.
The app is for free available in the Apple iTunes App Store for iPhone and iPad (search terms ‘gout diagnosis’). Language is English or Dutch (updates coming for German, French, and Spanish versions).