Risk factors for pseudogout in the general population
Young Hee Rho1, Yanyan Zhu1, Yuqing Zhang1, Anthony M. Reginato2and
Hyon K. Choi1
Objective. To evaluate the association between the purported risk factors for chondrocalcinosis and gout
and the risk of pseudogout in the general population.
Methods. We conducted a case?control study nested within a UK general practice database (The Health
Improvement Network) by identifying incident cases of pseudogout between 1986 and 2007 and up to 10
control subjects matched to each case, based on age, sex and follow-up time. We evaluated the pur-
ported risk factors for chondrocalcinosis (i.e. OA, RA, hyperparathyroidism and diuretics) and established
risk factors for gout (as comparison exposures) using conditional logistic regression analysis.
Results. We identified 795 cases of pseudogout and 7770 matched control subjects. The risk of pseu-
dogout was associated with hyperparathyroidism [odds ratio (OR) 4.87; 95% CI 2.10, 11.3], OA (OR 2.91;
95% CI 2.48, 3.43) and loop diuretic use (OR 1.35; 95% CI 1.09, 1.67). RA, thiazide diuretic use, BMI and
other gout risk factors were not associated with the risk of pseudogout, except for chronic renal failure
(OR 2.29; 95% CI 1.30, 4.01).
Conclusion. This general population study based on physician-recorded pseudogout suggests that most
of the previously observed associations with chondrocalcinosis are replicable with the risk of pseudogout,
but there are notable differences, such as thiazide diuretics, RA and chronic renal failure, highlighting the
need to study the clinical outcome, pseudogout. Avoiding loop diuretics may help individuals with recur-
Key words: pseudogout, chondrocalcinosis, CPPD, epidemiology.
Acute calcium pyrophosphate (CPP) crystal arthritis, or
pseudogout, is a common inflammatory arthritis of the
elderly population, and it belongs to a group of related
diseases (CPPDs), which also includes chondrocalci-
nosis . Recent recommendations by the European
risk factors for CPPD, such as age, OA, RA (inverse
However, the source data for these risk factors are limited
chondrocalcinosis . As chondrocalcinosis is often
asymptomatic, its risk factors may not garner the same
clinical interest as those for pseudogout. Furthermore, risk
factors for pseudogout may differ with chondrocalcinosis.
In this study, we sought to evaluate the relation between
the purported risk factors for chondrocalcinosis and the
risk of physician-recorded pseudogout in a general popu-
lation context. Given its gout-like clinical presentation, we
also investigated the potential impact of known risk
factors for gout, such as obesity, alcohol, hypertension,
diabetes, congestive heart failure and chronic kidney dis-
ease (as comparison exposures).
The Health Improvement Network (THIN) contains compu-
terized medical records entered by general practitioners
(GPs) in the UK . Data on ?7.3 million patients are sys-
tematically recorded and sent anonymously to THIN.
Patients included in the database are representative of
1Section of Rheumatology and the Clinical Epidemiology Unit, Boston
University School of Medicine, Boston, MA and2Warren Alpert
Medical School, Brown University, Providence, RI, USA.
Correspondence to: Hyon K. Choi, Section of Rheumatology and the
Clinical Epidemiology Unit, Boston University School of Medicine, 650
Albany Street, Suite 200, Boston, MA 02118, USA.
Submitted 2 April 2012; revised version accepted 25 June 2012.
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Advance Access publication 11 August 2012
by guest on January 8, 2016