Acute herpes zoster significantly affected quality of life and functional status. Sleep, enjoyment of life, general activities, mood, normal work, and the quality-of-life domains of pain or discomfort and usual activities were particularly affected. These findings were consistent across all age groups. Postherpetic neuralgia developed in 24% of the participants, with older patients being at greatest risk. Changes in quality of life over time closely correlated with the severity of pain and persisted as long as clinically significant pain continued. Participants with postherpetic neuralgia most frequently reported problems with anxiety or depression, enjoyment of life, mood and sleep.
Although the rash and pain associated with herpes zoster usually disappear within one month, our findings support the evidence that acute herpes zoster has a major impact on health-related quality of life and functional status.16,17,30
Significant impairment across different age groups indicated that younger patients were as likely as older ones to be affected by acute herpes zoster. At recruitment, the quality-of-life EQ-5D score was 0.59, as compared with 0.78 for the Canadian age-and sex-adjusted population.31
The difference between the two scores greatly exceeds a proposed cut-off of 0.07 for minimally important differences.32
Our findings confirm previous observations from cross-sectional surveys, which suggest that postherpetic neuralgia interferes mostly with enjoyment of life, mood, sleep and general activities.19
The 24% of participants who had postherpetic neuralgia in our study is higher than the proportion reported in the Shingles Prevention Study (12%).13
This difference is most likely because we included patients seeking care, whereas the other study included all actively sought patients, some of whom might not have otherwise sought care. However, our proportion of patients who had postherpetic neuralgia is similar to the proportion reported in a study in England (27%), which included a population seeking care for herpes zoster.14
Because older participants were more likely than younger ones to have postherpetic neuralgia and consequently experienced greater impairment in their quality of life, preventive measures may be most beneficial for these age groups. Clinicians should be aware that patients who continue to experience herpetic pain are likely to experience interference with activities of daily living, anxiety or depression, and insomnia and will need careful management of these conditions.
To make large-scale recruitment feasible and to reproduce real-life clinic conditions, we imposed minimal additional workload on recruiting physicians beyond that needed to treat their patients. For this reason, the main limitation of our study is that participation was not necessarily offered to all eligible patients, and the proportion of eligible patients who declined the invitation was not documented. However, our participants compared favourably with other study populations of patients with herpes zoster.10,33–35
Our results should thus be generalizable to patients seeking care for herpes zoster during the acute phase. Our data are also likely to present information bias such as learning effects because of repeated testing with the same instrument over time. Nonetheless, the close link between the change in severity of pain and quality of life over time provides some reassurance regarding the validity of our data. Finally, as in any prospective study assessing the influence of a disease on quality of life, a part of the change over time may have been attributable to response shifts.36,37
Although 90% of the study cohort was initially given antiviral treatment, herpes zoster and postherpetic neuralgia severely affected all health domains and activities of daily living. In addition, a recent Cochrane meta-analysis did not provide evidence to support the use of antivirals to prevent postherpetic neuralgia,38
although evidence is lacking for some specific antivirals.
Our study has several strengths. First, unlike studies that recruited patients with herpes zoster or postherpetic neuralgia at different intervals from rash onset and consequently were more subject to selection bias,18–20
we recruited patients at the time of diagnosis of herpes zoster and followed them long enough to allow the development of postherpetic neuralgia. Second, we described the change in specific health domains over time for participants with postherpetic neuralgia, unlike previous cross-sectional descriptions.18–20
Finally, we tested 41% of the eligible patients for the presence of varicella-zoster virus DNA and confirmed the diagnosis in 95% of those tested.
These results provide new information on the burden of herpes zoster and postherpetic neuralgia from the patient’s perspective. These data reinforce the need for effective preventive strategies, such as vaccination, and additional early intervention to reduce the burden of herpes zoster and postherpetic neuralgia.