Background/Purpose: Hospitalization of patients with gout may be associated with an increased risk of arthritic flares, due to administration of IV fluids, discontinuation of established uric acid lowering therapies and other medication changes. While previous studies have suggested an association of gouty arthritis and hospitalization, the absolute flare risk has not been identified. We aimed to determine the risk of flares with future hospitalizations and examine potential predictors of in-hospital gout flares.

Methods: We examined a population-based incidence cohort of patients with gout, diagnosed according to the New York, Rome or ACR preliminary criteria during two time periods:  1989 – 1992 and 2009 – 2010. All subjects were followed longitudinally through their complete medical records, until 5 years after their first gout attack, death or migration, whichever came first. Hospitalizations of each subject were recorded and hospital records were evaluated for a possible flare of gouty arthritis. Person-year methods were used to calculate the rate of flares of gouty arthritis during hospitalizations and out-of-hospital. In addition, mixed logistic regression models with random subject effects (accounting for multiple hospitalizations per subject) were used to explore risk factors of in-hospital gout flares.

Results:

429 patients with incident gout were followed for a mean of 4.2 years. The majority of patients were male (73%) and the mean age (SD) at gout onset was 59.7 (17.3).  169 patients had at least 1 hospitalization (cumulative incidence of first hospitalization was 39.1% for patients diagnosed in 1989-1992 compared to 43.1% for patients diagnosed in 2009-2010; p=0.56), with a total of 454 hospitalizations during the entire follow-up period. The rate of hospitalizations increased marginally from 2.26 per 10 person-years (py) in 1989-1992 to 3.49 per 10 py in 2009-2010 (rate ratio [RR]: 1.19; 95% confidence interval [CI]: 0.98, 1.45).

28 hospitalizations were complicated by a flare of gouty arthritis during a total of 3276 hospital days (9.0 total py) compared to 554 out-of hospital flares during 1784 py of follow-up. The rate of in-hospital flares was 85 per 100 py compared to 8.5 per 100 py out-of-hospital. Hospitalization was associated with a significantly increased risk of gout flares (RR: 10.2; 95% CI: 6.8, 14.5). In addition, the rate of in-hospital flares increased marginally over time (6.3 per 10 py in 1989-1992 vs 11.7 per 10 py in 2009-2010; RR: 1.85; 95% CI: 0.89, 4.00).

Various possible predictors of gout flares during hospitalization were evaluated, including discontinuation of established uric acid lowering therapy, administration of IV fluids, ICU admission, use of diuretics and reason for admission, but none were identified as statistically significant predictors of in-hospital flares.

Conclusion:

Hospitalization represents a significant risk factor for flares of gouty arthritis in patients with a prior diagnosis of gout, although the absolute risk is still low. Future studies are needed to clarify which patient subgroups are at particular risk and if inpatient care related measures can help to prevent arthritic flares during hospitalization.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/hospitalization-and-flare-risk-in-patients-with-established-gout-a-population-based-study-2/