Table 2. National age specific incidence of herpes zoster based on analysis of PBS antiviral prescriptions for herpes zoster.
| Age | July 2002 – June 2006 | July 2006 – June 2012 | ||||||
|---|---|---|---|---|---|---|---|---|
| Average Population 1 | Average Antiviral Prescriptions per year 2 | Estimated prescription rate per 1,000 persons (95% CI) 3 | Estimated zoster cases per 1,000 persons (95% CI) 4 | Average Population 1 | Average Antiviral Prescriptions per year 2 | Estimated prescription rate per 1,000 persons (95% CI) 3 | Estimated zoster cases per 1,000 persons (95% CI) 5 | |
| < 25 | 6,755,991 | 6,810 | 1.01 (1.00 – 1.02) | 1.95 (1.93 – 1.96) | 7,195,487 | 8,311 | 1.16 (1.15 – 1.17) | 2.00 (1.99 – 2.01) |
| 25 – 49 | 7,286,106 | 19,720 | 2.71 (2.69 – 2.73) | 5.22 (5.20 – 5.25) | 7,748,732 | 25,441 | 3.28 (3.27 – 3.30) | 5.68 (5.66 – 5.70) |
| 50 – 59 | 2,524,059 | 13,267 | 5.26 (5.21 – 5.30) | 7.84 (7.79 – 7.90) | 2,749,976 | 16,486 | 6.00 (5.96 – 6.03) | 8.65 (8.61 – 8.70) |
| 60 – 69 | 1,660,706 | 12,937 | 7.79 (7.72 – 7.86) | 11.63 (11.54 – 11.71) | 2,059,052 | 18,145 | 8.81 (8.76 – 8.86) | 12.72 (12.65 – 12.78) |
| 70 – 79 | 1,162,886 | 10,917 | 9.38 (9.30 – 9.47) | 14.01 (13.90 – 14.12) | 1,248,226 | 13,905 | 11.14 (11.06 – 11.22) | 16.07 (15.98 – 16.16) |
| 80+ | 680,569 | 6,122 | 9.00 (8.88 – 9.11) | 13.43 (13.29 – 13.56) | 809,216 | 8,568 | 10.59 (10.50 – 10.68) | 15.28 (15.17 – 15.39) |
Bolded data in table indicates statistically significant results.
1. Average estimated resident population of Australia. Australian Bureau of Statistics (ABS). 3101.0—Australian Demographic Statistics, Jun 2013, available at http://www.abs.gov.au/ausstats/abs@.nsf/mf/3101.0; June 2003 to June 2012 populations were assigned to the 2002–03 to 2011–12 financial years respectively.
2. Prescription numbers estimated from scripts supplied to a sample of the Australian population drawn from PBS payment records by financial year from July 2002—June 2012. Note for the July 2002—June 2006 period there were very minor differences from estimates presented in (Stein et al 2009), reflecting changes in the updated dataset.
3. Rates estimated using the “ci” command in Stata version 11.2, with Poisson 95% confidence intervals and population defined as the exposure variable, reflecting the variability in annual numbers of antiviral prescriptions.
4. Extrapolated from annual antiviral prescriptions for herpes zoster recorded on the PBS, adjusted for the proportion of encounters for a new zoster problem in which antivirals are prescribed, derived from the BEACH database (51.8% and 67.0% for those aged less than 50 years or 50 years and older respectively). Rates estimated using the “ci” command in Stata version 11.2, with Poisson 95% confidence intervals and population defined as the exposure variable, reflecting the variability in annual numbers of antiviral prescriptions.
5. Extrapolated from annual antiviral prescriptions for herpes zoster recorded on the PBS, adjusted for the proportion of encounters for a new zoster problem in which antivirals are prescribed, derived from the BEACH database (57.8% and 69.3% for those aged less than 50 years or 50 years and older respectively). Rates estimated using the “ci” command in Stata version 11.2, with Poisson 95% confidence intervals and population defined as the exposure variable, reflecting the variability in annual numbers of antiviral prescriptions.