Referral Characteristics and Outcomes in Rheumatology Outpatient Referrals: A Single-Center Observational Study

INTRODUCTION: Referrals to rheumatology outpatient clinics have increased worldwide, contributing to prolonged waiting times and challenges in accessing specialized care. A substantial proportion of referred patients ultimately do not receive a rheumatologic diagnosis, often due to nonspecific complaints or inappropriate referral indications. This study aimed to evaluate referral patterns, diagnostic yield, and clinical outcomes according to referral source in a rheumatology outpatient clinic.
METHODS: This retrospective single-center observational study included 400 patients over a nine-month period. Demographic characteristics, referral reasons, referral sources, laboratory parameters and final diagnoses were recorded. Comparative statistical analyses were performed between referral groups. Firth’s penalized logistic regression analysis was additionally used to address quasi-complete separation in multivariable analysis.
RESULTS: Overall, 79.3% of patients received a rheumatologic diagnosis. Internal medicine accounted for the majority of referrals (75.8%) and demonstrated a significantly higher diagnostic yield compared with primary care referrals (91.4% vs. 53.1%, p < 0.001). Crystal-induced arthropathies represented the most frequent diagnostic category, followed by spondyloarthritis spectrum disorders and rheumatoid arthritis. ANA positivity was significantly associated with rheumatologic diagnosis. Using Firth’s penalized logistic regression, referral from internal medicine remained independently associated with rheumatologic diagnosis (OR 5.03, 95% CI 2.38–10.61, p < 0.001), while ANA positivity was also independently associated (OR 3.28, 95% CI 1.15–9.34, p = 0.026).
DISCUSSION AND CONCLUSION: Referral source is associated with substantial differences in diagnostic yield in rheumatology outpatient care. These findings likely reflect variations in pre-referral evaluation rather than intrinsic differences in diagnostic accuracy. Structured referral strategies and standardized triage approaches may help optimize specialist resource utilization.

Keywords: outpatient clinics hospital, outpatients, referral and consultation