Risk of herpes zoster in CKD: a matched-cohort study based on administrative data.

BACKGROUND

Immune system dysregulation is associated with end-stage renal disease. Although decreased cellular immunity increases susceptibility to herpes zoster, the risk of herpes zoster in patients with earlier stages of chronic kidney disease (CKD) is unclear.

STUDY DESIGN

A matched-cohort study.

SETTING & PARTICIPANTS: Data from the Taiwan Longitudinal Health Insurance Database (LHID) for 2004-2006 were analyzed. The study cohort included patients 18 years or older given a diagnosis of CKD (excluding patients treated by dialysis or transplant) in 2004-2005 (n = 13,321). The comparison cohort (n = 66,605) included 5 randomly selected age- and sex-matched controls for each patient in the study cohort.

PREDICTOR

CKD. Incident cases of CKD were identified using the Taiwan LHID. CKD was ascertained from International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) codes.

OUTCOMES

Herpes zoster, ascertained from ICD-9-CM codes. All participants were followed up from the date of cohort entry until they developed herpes zoster or the end of 2006. Cox proportional hazard regressions were performed to compare the hazard rates of herpes zoster in the CKD cohort and the age- and sex-matched comparison cohort.

RESULTS

We identified 13,321 patients with a diagnosis of CKD who matched the inclusion criteria. 1,602 patients developed herpes zoster during the study period, of whom 353 were from the CKD cohort and 1,249 were from the comparison cohort. After adjusting for potential confounding factors, CKD was associated independently with greater risk of herpes zoster (HR, 1.60; 95% CI, 1.41-1.81).

LIMITATIONS

Some patients with CKD or herpes zoster may have chosen not to seek medical care. Misclassification of CKD due to use of diagnostic codes also is a limitation.

CONCLUSIONS

This population-based cohort study indicated that patients with CKD are at increased risk of herpes zoster compared with the general population.