Ana Maria Herrero-Beites, Cristina Vázquez-Puente, Maria Del Consuelo Modesto-Caballero, Fernando Pérez-Ruiz
Affiliation(s):
Rheumatology Division, Cruces University Hospital
Background: non-rational prescription of examinations in clinical practice may induce inefficient performances, misdiagnosis, and inappropriate consultations.
Objective: we analyzed the prescription and results of antinuclear antibodies (ANA) prescription before first consultation to a rheumatology unit in a disease with commonly high diagnostic accuracy based on clinical findings: gout.
Methods: from 2013 onwards prescription and results of ANA testing prior to first rheumatology visit was added to the database, along with general data and variables related to comorbid conditions and clinical characteristics of gout. We made an analysis of variables plausibly associated with ANA prescription and biennial changes through n the rate of prescription.
Results: from 2013 to 2022, 504 patients gave written consent for data inclusion, 66 (13.7%) women and 415 men (86,3%), with mean age at entrance in the cohort of 73±14 and 65±14 years, respectively. ANA had been prescribed to 114 (23.7%) subjects, in 28/66 (42.4%) women and 86/415 men (p<0,001). No differences for prescription were observed in other variables, such as age, time from onset, flares per year, tophi, or polyarticular distribution. The rate of ANA prescription was not related to the diagnostic for derivation: arthralgia (24.4%), arthritis (21.7%) or gout (25,3%). 31/114 (27.2%) ANA tests were positive (90% with title <1/400), but only led to a new diagnosis (autoimmune hepatitis), and two had a previous diagnosis (Sjögren´s Syndrome and Systemic Lupus). The rate of positive ANA was much higher in women (12/28, 42.9%) than in men (8/86, 22.1%). The rate of ANA prescriptions showed a biennial and significative increase during the last decade (p= 0.007): 11.3% in 2013-14, 21.4% in 2015-16, 34.9% in 1016-2017, and 31.1% in 2021-22. A valley in ANA prescriptions was observed during SARS-COV2 pandemia 2019-2020 (19.7%).
Conclusions: in a disease with quite typical clinical presentation as gout is, the rate of ANA prescription prior to rheumatology consultation is high, and especially high in women, despite old age and absence of systemic clinic. The rate of positive ANA tsting is quite high, close to 50% in women, and may lead to misdiagnosis and inefficient management: the new VOMIT.