Incidence of herpes zoster and its complications in ≥ 50-year-old Spanish adults: A prospective cohort study

Abstract

IntroductionHerpes zoster (HZ) chiefly affects older individuals and the immunocompromised and may lead to persistent pain, postherpetic neuralgia (PHN), and other complications. MethodsFrom 2012–2015, we conducted a prospective observational cohort study of adults ≥50 years with HZ presenting in primary care in Spain (NCT01521286). We estimated HZ incidence rates (IR) per 1,000 person-years (PY) over a 12-month period, and prospectively followed up a broader patient cohort; assessing pain severity using the ‘Zoster Brief Pain Inventory (ZBPI) and PHN development (defined as ZBPI ‘worst pain’ ≥3 at Day 90). ResultsHZ IR in adults ≥50 years was 4.88/1,000 PY (95% confidence interval [CI]: 4.44–5.35), similar for both genders. Incidence increased with age, from 2.54 (95% CI: 1.84–3.41) in 50–54-year-olds to 6.40/1,000 PY (95% CI: 4.86–8.28) in 75–79-year-olds. In 545 HZ patients followed prospectively, the proportion of HZ patients with PHN was 4.59% (95% CI: 2.99–6.70); and 11.79% (95% CI: 7.78–16.91) in those 212 patients with available ZBPI scores at Day 90. The proportion of patients developing PHN increased with increasing age. Mean ZBPI ‘worst pain’ scores in patients not developing PHN showed a marked decline between Day 0–30 (from 5.4 to 1.6) and none at Day 90; in patients with PHN this score remained high (>5.5) up to Day 150. Other complications were observed in 10.3% of patients. ConclusionsHZ presents a considerable burden in adults aged ≥50 years in Spain, with an IR of ~5/1,000 PY. HZ and PHN risk increased with age.