Existing criteria for the classification of gout have suboptimal sensitivity and/or specificity, and were developed at a time when advanced imaging was not…

You may be wondering, “Why would we need guidelines to diagnose Gout?” You may think it’s a no-brainer even for the man-on-the-street, but reading yesterday’s post on Gout the Great Mimic should make us less sanguine.
The other reason is a financial one. New, highly effective but very costly treatments have emerged for Gout, as they did for RA. Canakinumab, an anti-IL1 effective in controlling refractory Gout inflammation, costs $20,000 per pop. Gone are the days when insurers accept the doctor’s diagnosis as the gold standard. These days, patients must meet certain diagnostic criteria and fulfil certain conditions (like, tried and failed cheaper treatment options) before insurers will pay.
There is a catch: these are “Classification Criteria” and not “Diagnostic Criteria”. What is the difference? “Classification Criteria” are used to ensure homogeneity of patient population for enrollment into clinical studies (eg to test whether a new drug works for a particular disease), thus the criteria are stringent and favour specificity (keep out “non-disease” from trial). “Diagnostic Criteria” favour sensitivity: you don’t want to miss out anyone with the disease for treatment. As in the 2010 ACR/EULAR RA Classification Criteria, specificity has been sacrificed for sensitivity, in order to avail the new and effective drugs to more patients, at risk of over-treatment (remember, we doctors are always siding with the patients😇). Therefore in clinical practice, Classification Criteria have served as Diagnostic Criteria, especially in reimbursed markets. Doctors of patients with deep pockets still follow the Stewart’s rule (on hardcore pornography): “I know it when I see it”😊

2015 ACR-EULAR Gout Criteria Scoring summary slides

In 2015, ACR and EULAR issued classification criteria for gout. The scoring system is summarized here in an easy to use format for physicians and patients.