Predicting postherpetic neuralgia in elderly primary care patients with herpes zoster: prospective prognostic study

Development of a Prediction Model and Corresponding Scoring Table for Postherpetic Neuralgia Using Six Machine Learning Algorithms: A Retrospective Study

INTRODUCTION

Postherpetic neuralgia (PHN), a complication of herpes zoster, significantly impacts the quality of life of affected patients. Research indicates that early intervention for pain can reduce the occurrence or severity of PHN. This study aims to develop a predictive model and scoring table to identify patients at risk of developing PHN following acute herpetic neuralgia, facilitating informed clinical decision-making.

METHODS

We conducted a retrospective review of 524 hospitalized patients with herpes zoster at The First Affiliated Hospital of Zhejiang Chinese Medical University from December 2020 to December 2023 and classified them according to whether they had PHN, collecting a comprehensive set of 30 patient characteristics and disease-related indicators, 5 comorbidity indicators, 2 disease score values, and 10 serological indicators. Relevant features associated with PHN were identified using the least absolute shrinkage and selection operator (LASSO). Then, the patients were divided into a training set and a test set in a 4:1 ratio, with comparability tested using univariate analysis. Six models were established in the training set using machine learning methods: support vector machines, logistic regression, random forest, k-nearest neighbor, gradient boosting, and neural network. The performance of these models was evaluated in the test set, and a nomogram based on logistic regression was used to create a PHN prediction score table.

RESULTS

Eight non-zero characteristic variables selected from the LASSO regression results were included in the model, including age [area under the curve (AUC) = 0.812, p < 0.001], Numerical Rating Scale (NRS) (AUC = 0.792, p < 0.001), receiving treatment time (AUC = 0.612, p < 0.001), rash recovery time (AUC = 0.680, p < 0.001), history of malignant tumor (AUC = 0.539, p < 0.001), history of diabetes (AUC = 0.638, p < 0.001), varicella-zoster virus immunoglobulin M (AUC = 0.620, p < 0.001), and serum nerve-specific enolase (AUC = 0.659, p < 0,001). The gradient boosting model outperformed other classifier models on the test set with an AUC of 0.931, 95% confidence interval (CI) (0.882-0.980), accuracy of 0.886 (95% CI 0.809-0.940). In the test set, our predictive scoring table achieved an AUC of 0.820 (95% CI 0.869-0.970) with accuracy of 0.790 (95% CI 0.700-0.864).

CONCLUSION

This study presents a methodology for predicting the development of postherpetic neuralgia in shingles patients by analyzing historical case data, employing various machine learning techniques, and selecting the optimal model through comparative analysis. In addition, a logistic regression model has been used to create a scoring table for predicting the postherpetic neuralgia.

Circulating Level of Myelin Basic Protein Predicts Postherpetic Neuralgia: A Prospective Study

OBJECTIVES

Patients with herpes zoster (HZ) would benefit from accurate prediction of whether they are likely to develop postherpetic neuralgia (PHN). We investigated whether a circulating biomarker of neuronal damage could be a predictor of PHN in this nonmatched prospective, nested, case-control study.

MATERIALS AND METHODS

We included patients with HZ who were within 90 days after rash onset. Volunteers without a history of HZ were recruited as controls. We evaluated epidemiologic factors and circulating neuronal damage biomarkers, including cell-free DNA, myelin basic protein (MBP), and soluble protein-100B (S100B). We conducted logistic regression analyses to develop a prediction model of PHN.

RESULTS

We found that cell-free DNA and MBP levels were higher in patients with HZ (n=71) than in controls (n=37). However, only MBP level was higher in patients who developed PHN (n=25), in comparison with those who did not (n=46). MBP level and 3 clinical factors, age, acute pain severity, and response to treatment drugs were identified as independent predictors of PHN. Receiver operating characteristic (ROC) curve analysis showed that the prediction made using a combination of MBP level and clinical factors had an area under ROC curve of 0.853 (95% confidence interval: 0.764 to 0.943), which was better than prediction using clinical factors alone (area under ROC curve: 0.823, 95% confidence interval: 0.728 to 0.917).

DISCUSSION

Our results indicate that circulating MBP level in patients with HZ is a predictor for PHN. The combination of clinical predictors and MBP level enhanced the prediction performance.

Efficacy of repetitive paravertebral block combined with medication in the treatment of zoster-related pain with different courses

Objectives:

To compare the clinical outcomes of repetitive paravertebral block (PVB) combining oral medication in the treatment of zoster-related pain (ZP) with different courses.

Methods:

Sixty-seven patients with ZP were divided into 3 groups based on their course of herpes zoster (HZ). Group I: 24 patients with acute herpetic neuralgia (within one month of disease onset); group II: 22 patients with subacute herpetic neuralgia (disease onset from 1 to 3 months); group III: 21 patients with postherpetic neuralgia (more than 3 months since disease onset). All patients received ultrasound-guided repetitive PVB with oral gabapentin and tramadol sustained-release tablets. The VAS and QS scores and the incidences of hematoma, dizziness, nausea, and drowsiness were compared at 1 day, 3 months, and 6 months after treatment.

Results:

Pain intensity and sleep quality of the 3 groups improved to varying degrees after treatment. The best efficacy was achieved in the acute group, followed by the subacute group, and the poorest efficacy was observed in the chronic group.

Conclusion:

The efficacy of ultrasound-guided repetitive PVB with oral medication varied with the courses of HZ. The shorter the time since onset, the better the efficacy. This combined treatment showed better efficacy in patients at the acute and subacute stages and significantly improved their pain and sleep quality, while demonstrating limited pain relief in chronic patients.

Different dosages of valaciclovir for the treatment of herpes zoster in adults: A randomized clinical study

WHAT IS KNOWN AND OBJECTIVE

The dosages of valaciclovir used for herpes zoster treatment recommended by Chinese pharmaceutical companies can differ considerably from those reported in the literature. This randomized clinical study compares the efficacy and safety of different oral valaciclovir doses for the treatment of herpes zoster in adults.

METHODS

A total of 214 patients with herpes zoster were enrolled and randomized into two groups according to age: 98 patients in the 18-44-year group (younger patients) and 116 patients in the 45-74-year group (middle-aged and elderly patients). Patients in the two age groups were then prescribed different doses of valaciclovir. The high-dose group was administered 900 mg of valaciclovir, three times daily for 10 days, whereas the low-dose group was administered 300 mg of valaciclovir, two times daily for 10 days. The efficacy and side effects of these regimens were recorded on days 6, 11 and 30.

RESULTS

In total, 207 (of 214 enrolled) patients completed the study. Of the seven patients who discontinued the study, five discontinued because their follow-up time was not fixed and two withdrew after moving to other cities. At the 11th day after treatment, the clinical effect of high-dose valaciclovir groups were significantly better than that of the low-dose valaciclovir groups in middle-aged and elderly patients (p < 0.05). The difference in visual analog scale (VAS) pain scores between the two dose groups was statistically significant in middle-aged and elderly patients at the 6th day(p < 0.05), whereas there was no difference in younger patients (p > 0.05). The VAS scores were significantly lower in high-dose group than in low-dose group at day 11 in both groups of patients(p < 0.05).There was no statistically significant difference in the time to skin scab improvement between the two different dose groups in younger patients (p > 0.05). Among middle-aged and elderly patients, the incidence of postherpetic neuralgia (PHN) was significantly lower in the high-dose group than in the low-dose group (p < 0.05). The difference in the incidence of adverse reactions between the high-dose and low-dose groups was not statistically significant (p > 0.05). Overall, the main side effect was headache.

WHAT IS NEW AND CONCLUSION

The present study indicates that early treatment with high-dose valaciclovir can significantly reduce pain in patients, especially in elderly patients, in whom it can also reduce the incidence of PHN. In terms of safety, no significant difference was noted in the incidence of adverse reactions between high- and low-dose groups.

Effectiveness and cost-effectiveness of vaccination against herpes zoster in Canada: a modelling study

BACKGROUND

Two vaccines against herpes zoster are currently authorized for use in Canada: the recombinant subunit zoster vaccine and live attenuated zoster vaccine. We compared the effectiveness and cost-effectiveness of these 2 vaccines.

METHODS

We used a decision analytic static cohort model parametrized with Canadian epidemiologic and economic data. We performed the economic analysis from the health care system perspective, using a lifetime horizon and a 3% discount rate for costs and benefits. The primary outcome was the incremental cost per quality-adjusted life-year (QALY) gained, relative to no vaccination. We ran 30 000 simulations varying all model parameters, including vaccine costs, efficacy and waning.

RESULTS

The number needed to vaccinate (NNV) was higher for the live attenuated zoster vaccine than for the recombinant subunit zoster vaccine for all herpes zoster-related events at all ages. For example, in persons exactly 65 years old, for herpes zoster, median NNV was 21 (90% uncertainty interval [UI] 13-31) versus 8 (90% UI 6-18), and for postherpetic neuralgia, NNV was 64 (90% UI 33-93) versus 31 (90% UI 23-73). For the recombinant vaccine, the median cost-effectiveness ratios varied between cost-saving and $25 881 per QALY gained for adults aged 50 years or older. For the live vaccine, the cost-effectiveness ratios varied between cost-saving and $130 587 per QALY gained and were less than $45 000 per QALY gained only for those 65 to 75 years old. Given its higher efficacy, we estimated that the cost for the complete series of the recombinant vaccine could be $150 to $200 more than the cost of the live vaccine and still be considered cost-effective.

INTERPRETATION

Our model predicted that the recombinant subunit zoster vaccine is likely cost-effective in Canada for adults 60 years or older, and is likely more cost-effective than live attenuated zoster vaccine. These results have informed updated national and provincial recommendations on herpes zoster vaccination.

VZV-specific cell-mediated immunity, but not humoral immunity, correlates inversely with the incidence of herpes zoster and the severity of skin symptoms and zoster-associated pain: The SHEZ study

Onset of herpes zoster (HZ) is thought to be related to a decline in cell-mediated immunity (CMI). However, until recently, there have been no large-scale prospective studies on the relationship between varicella-zoster virus (VZV)-specific CMI and the onset and severity of HZ. The Japanese researchers conducted a cohort study on VZV immunity in a population living on an island cluster, Shozu County in Japan, and examined the people who developed HZ during a follow-up period of three years to clarify the relationship between the onset and severity of HZ and immunity. In this study, they focused on the relationship between cell-mediated and humoral immunity and the onset and severity of HZ. CMI was measured by VZV skin test, and humoral immunity was assessed with serological tests for VZV-specific antibodies. A total of 12,522 people over the age of 50 were enrolled in this study, and 401 registrants were diagnosed as HZ. VZV-specific CMI assessed by VZV skin test showed a significant inverse relationship with the incidence of HZ and the severity of skin lesions and acute and subacute pain, and with the occurrence of postherpetic neuralgia. In contrast, VZV-specific antibody titer was not associated with the incidence and severity of HZ. These results suggest that VZV-specific CMI, but not humoral immunity, plays a key role in controlling the onset of HZ, the severity of skin lesions, and zoster-associated pain.

Somatosensory profiles in acute herpes zoster and predictors of postherpetic neuralgia

This prospective cohort study aimed to characterize the sensory profile during acute herpes zoster (AHZ) and to explore sensory signs as well as physical and psychosocial health as predictors for postherpetic neuralgia (PHN). Results of quantitative sensory testing of 74 patients with AHZ at the affected site and at the distant contralateral control site were compared to a healthy control group. Pain characteristics (Neuropathic Pain and Symptom Inventory and SES), physical functioning, and psychosocial health aspects (Pain Disability Index, SF-36, and STAI) were assessed by questionnaires. Patients with PHN (n = 13) at 6-month follow-up were compared to those without PHN (n = 45). Sensory signs at the affected site were thermal and vibratory hypesthesia, dynamic mechanical allodynia (DMA), pressure hyperalgesia, and high wind-up (18%-29%), as well as paradoxical heat sensations and pinprick hypalgesia (13.5%). The unaffected control site exhibited thermal and vibratory hypesthesia, DMA, and pressure hyperalgesia. Dynamic mechanical allodynia and pinprick hypalgesia were mutually exclusive. Postherpetic neuralgia was associated with DMA (38.5% vs 6.7%; P = 0.010) and vibratory hypesthesia (38.5% vs 11.1%; P = 0.036) at the control site, with mechanical gain and/or loss combined with normal thermal detection (affected site: 69.2% vs 31.1%; P = 0.023; control site: 53.8% vs 15.5%; P = 0.009). Pain Disability Index (P = 0.036) and SES affective pain perception scores (P = 0.031) were over 50% higher, and 6 of 8 SF-36 subscores were over 50% lower (P < 0.045) in PHN. Sensory profiles in AHZ indicate deafferentation and central but not peripheral sensitization. Sensory signs at distant body sites, strong affective pain perception, as well as reduced quality of life and physical functioning in the acute phase may reflect risk factors for the transition to PHN.

Parameters associated with efficacy of epidural steroid injections in the management of postherpetic neuralgia: the Mayo Clinic experience

Purpose: Thirty percent of patients with postherpetic neuralgia (PHN) receiving conservative treatment report unsatisfactory pain relief. Epidural steroid injections (ESIs) are commonly used as a therapeutic intervention in these patients. In this study, we aimed to determine if there are variables that predict the efficacy of ESI in patients with PHN.

Patients and methods: We retrospectively identified patients seen at Mayo Clinic who had PHN and received ESI. From their medical records, we abstracted the demographic variables, concurrent medication use, anatomic approach and medication for ESI, and degree of pain relief at 2 and 12 weeks' postintervention.

Results: None of the studied variables were significantly associated with efficacy of ESI in patients with PHN. PHN that began <11 months before treatment was predictive of a response to ESI at 12 weeks postintervention (positive predictive value, 55%). Patients who reported poor ESI efficacy 2 weeks after the intervention had a 94% chance of still having pain at 12 weeks.

Conclusion: For this cohort of patients with PHN being treated with ESI, no demographic characteristics, concurrently used medications, or type of ESI were associated with ESI treatment efficacy at 2 or 12 weeks after the intervention.

Post-herpes neurotrophic keratopathy: Aetiopathogenesis, clinical signs and current therapies

Neurotrophic keratopathy (NK) is a degenerative corneal disease caused by damage of trigeminal innervation. This leads to epithelial defects, ulceration and, eventually, perforation. Both herpes simplex and varicella zoster keratitis are reported to be the main causes of NK. Furthermore, prognosis in this type of NK is poor. Classic clinical findings in post-herpes NK are spontaneous epithelial breakdown, round and central epithelial defects with smooth edges, stromal melting and thinning, scarring, and neovascularisation. Although several medical and surgical treatments have been reported, no therapies are currently available to definitely restore corneal sensitivity. Therefore, NK remains a challenging disease to treat. In this review a summary is presented of the pathogenesis, manifestations, and current management of post-herpes NK. The role of antiviral treatment and varicella-zoster vaccination is also discussed. A description is also presented on both medical and surgical novel therapies, such as regenerative drugs and corneal neurotization.

Comparison of Famciclovir, Valaciclovir, and Brivudine Treatments in Adult Immunocompetent Patients With Herpes Zoster

Herpes zoster (HZ) is a common disease characterized by the recurrence of varicella zoster, that stays dormant in sensory ganglia. The primary goal of this study was to compare efficiencies of famciclovir, valaciclovir, and brivudine in terms of pain relief in HZ patients. Records of patients who were admitted to the Dermatology Clinic of our hospital due to acute HZ between the years 2012 and 2014 were retrospectively analyzed. Treatment decisions were at the discretion of caring physicians as valaciclovir (VACV), famciclovir (FCV), and brivudine (BRV) based on the clinical observations. BRV, FCV, and VACV were effective in treating pain in acute HZ. There was no significant difference between mild and moderate HZ patients. In severe cases, a significant reduction in intensity of pain was observed on day 3 in the BRV group, on day 7 in the FCV group, and at 2-3 weeks in the VACV group. There were no significant side effects observed in any of the groups. Results of this study indicate that brivudine may be the first choice in severe HZ cases as it controls pain earlier and is easier to use because of its once daily administration.

Premedication With Gabapentin Significantly Reduces the Risk of Postherpetic Neuralgia in Patients With Neuropathy

Postherpetic neuralgia (PHN) is the most common complication of varicella zoster virus (VZV) reactivation and a cause of considerable physical and psychosocial morbidity. No known treatment effectively prevents the development of PHN in patients with VZV reactivation. In this study, our objective was to evaluate the efficacy of premedication with gabapentin for reducing the risk of PHN in patients with diabetic and nondiabetic neuropathy. We retrospectively searched the electronic health records of patients with diabetic and nondiabetic neuropathy treated with gabapentin at Mayo Clinic before diagnosis of VZV reactivation. In total, PHN developed in 7 patients with diabetic neuropathy receiving gabapentin (n=62 [11.3%]) compared with 26 not receiving premedication with gabapentin (n=50 [52.0%]) (odds ratio, 0.12; 95% CI, 0.05-0.31; P<.001); PHN developed in 11 patients with nondiabetic neuropathy receiving gabapentin (n=109 [10.1%]) compared with 108 not receiving premedication with gabapentin (n=217 [49.8%]) (odds ratio, 0.11; 95% CI, 0.06-0.22; P<.001). In this cohort of patients with neuropathy, gabapentin administration before the onset of VZV reactivation significantly reduced the risk of PHN.

Burden of herpes zoster in 16 selected immunocompromised populations in England: a cohort study in the Clinical Practice Research Datalink 2000-2012

OBJECTIVES

Herpes zoster (HZ) is caused by reactivation of varicella-zoster virus which remains latent in individuals after a varicella infection. It is expected that HZ will be more frequent in immunocompromised (IC) individuals than in immunocompetent (IC-free). This study assessed the incidence rate (IR) of HZ in individuals with a wide set of IC conditions and in IC-free individuals.

SETTING

A retrospective cohort study was conducted in England using data (January 2000 to March 2012) from the Clinical Practice Research Datalink with linkage to the Hospital Episodes Statistics.

PARTICIPANTS

A cohort of 621 588 individuals with 16 selected IC conditions and a gender/age-matched cohort of IC-free individuals were identified. The IC conditions included haematopoietic stem cell transplant (HSCT), solid organ transplant, malignancies, autoimmune diseases and users of immunosuppressive medications.

OUTCOMES

IR of HZ per 1000 person-years (PY) was estimated. Proportions of postherpetic neuralgia (PHN) and other HZ complications within 90 days of HZ onset were also estimated among patients with HZ. Risk factors for PHN in IC individuals with HZ were assessed by a multivariate regression model.

RESULTS

The overall IR of HZ in the IC cohort was 7.8/1000 PY (95% CI 7.7 to 7.9), increasing with age from 3.5/1000 PY (3.4-3.7) in individuals aged 18-49 years to 12.6/1000 PY (12.2-13.0) in individuals aged ≥80 years. This IR in the IC-free cohort was 6.2/1000 PY (6.1-6.3). The overall IR of HZ varied across IC conditions, ranging from 5.3 (5.1-5.5) in psoriasis to 41.7/1000 PY (35.7-48.4) in HSCT. The proportions of PHN and other HZ complications were 10.7% (10.2-11.1) and 2.9% (2.7-3.2) in the IC cohort, but 9.1% (8.7-9.5) and 2.3% (2.1-2.6) in the IC-free cohort, respectively.

CONCLUSION

IC population contributes to the public health burden of HZ in England. Vaccination might be the most preferable HZ preventive measure for the IC population.

Incidence and costs of herpes zoster and postherpetic neuralgia in German adults aged ≥50 years: A prospective study

OBJECTIVES

Herpes zoster (HZ) mainly affects elderly people and immunocompromised individuals. HZ is usually characterized by a unilateral painful skin rash. Its most common complication, postherpetic neuralgia (PHN), may cause chronic debilitating pain. This study aimed to estimate the HZ incidence in individuals aged ≥50 years in Germany, the proportion of PHN and the economic burden.

METHODS

From 2010 to 2014, HZ patients were recruited when consulting physicians in physician networks covering about 157,000 persons aged ≥50 years. PHN was defined as "worst pain" rated ≥3 on the zoster brief pain inventory persisting or appearing over 90 days after rash onset. Costs were calculated based on medical resource utilization and lost working time.

RESULTS

HZ incidence was estimated as 6.7/1000 person-years, increasing with age to 9.4/1000 in ≥80 year-olds. Among 513 HZ patients enrolled, the proportion of PHN was 11.9%, rising with age to 14.3% in HZ patients ≥80 years. Estimated total cost per HZ patient was €156 from the healthcare system perspective and €311 from the societal perspective.

CONCLUSIONS

The study confirmed previous findings that HZ causes a substantial clinical and economic burden in older German adults. It also confirmed the age-related increasing risk of HZ and PHN.

Effectiveness of continuous epidural analgesia on acute herpes zoster and postherpetic neuralgia: A retrospective study

Despite early treatment of herpes zoster (HZ), postherpetic neuralgia (PHN) can persist. This study was designed to compare the therapeutic and pain relief effects of continuous epidural analgesia (CEA) on the chronic phase as well as the acute phase of HZ with standard medical treatment.Medical records of 227 patients with moderate to severe zoster-associated pain that had not responded to standard medications were retrospectively reviewed. Patients received standard treatment alone (medical group) or standard treatment plus concurrent CEA (epidural group). The acute and chronic groups were classified according to a 4-week cut-off with regard to time between the onset of the rash and the first treatment. Four groups were studied: Group A (acute/medical group); Group B (acute/epidural group); Group C (chronic/medical group); and Group D (chronic/epidural group). Pain was assessed using the visual analog scale (VAS) and measured every 2 weeks for 6 months. We compared the pain rating at 6 months after the first treatment with the initial pain rating. Response to treatment was defined as a ≥50% reduction in pain severity since the initial visit. Remission was considered complete for patients whose VAS pain score was ≤2 for >3 successive visits and who no longer needed medical support.Patients who received a combination of standard treatment plus CEA (Groups B and D) had significantly higher response to treatment (P = .001) than patients receiving standard treatment alone (Groups A and C). The adjusted odds ratio (OR) for response to treatment in the epidural group versus the medical group was 5.17 (95% confidence interval [CI]: 1.75-15.23) in the acute group and 5.37 (95% CI: 1.62-17.79) in the chronic groups. The adjusted OR for complete remission in the epidural group versus the medical group was 3.05 (95% CI: 1.20-7.73) in the acute group and 4.46 (95% CI: 1.20-16.54) in the chronic group.CEA can effectively relieve pain caused by PHN and acute HZ and increase remission rates. Combining CEA with standard medical treatment may offer a clinical advantage in the management of pain caused by PHN as well as acute HZ.

Effects of applying nerve blocks to prevent postherpetic neuralgia in patients with acute herpes zoster: a systematic review and meta-analysis

BACKGROUND

Postherpetic neuralgia (PHN) is a common and painful complication of acute herpes zoster. In some cases, it is refractory to medical treatment. Preventing its occurrence is an important issue. We hypothesized that applying nerve blocks during the acute phase of herpes zoster could reduce PHN incidence by attenuating central sensitization and minimizing nerve damage and the anti-inflammatory effects of local anesthetics and steroids.

METHODS

This systematic review and meta-analysis evaluates the efficacy of using nerve blocks to prevent PHN. We searched the MEDLINE, EMBASE, Cochrane Library, ClinicalTrials.gov and KoreaMed databases without language restrictions on April, 30 2014. We included all randomized controlled trials performed within 3 weeks after the onset of herpes zoster in order to compare nerve blocks vs active placebo and standard therapy.

RESULTS

Nine trials were included in this systematic review and meta-analysis. Nerve blocks reduced the duration of herpes zoster-related pain and PHN incidence of at 3, 6, and 12 months after final intervention. Stellate ganglion block and single epidural injection did not achieve positive outcomes, but administering paravertebral blockage and continuous/repeated epidural blocks reduced PHN incidence at 3 months. None of the included trials reported clinically meaningful serious adverse events.

CONCLUSIONS

Applying nerve blocks during the acute phase of the herpes zoster shortens the duration of zoster-related pain, and somatic blocks (including paravertebral and repeated/continuous epidural blocks) are recommended to prevent PHN. In future studies, consensus-based PHN definitions, clinical cutoff points that define successful treatment outcomes and standardized outcome-assessment tools will be needed.

Pain, Itch, Quality of Life, and Costs after Herpes Zoster

BACKGROUND

Herpes zoster (HZ) and postherpetic neuralgia are known to have a profound effect on the patient's quality of life, but the incidence and severity of itch and its relation with pain and quality of life in the long term are still relatively unknown.

OBJECTIVE

The aim of this study was to measure the presence and severity of pain and itch and impact on quality of life in patients over 50 years old with HZ.

METHODS

We enrolled 661 patients with HZ in this 12-month observational study. Patient data were collected via a web-based questionnaire. Outcomes were pain, itch, burden of illness, impact on patient's daily life, impact on quality of life, and healthcare costs.

RESULTS

At inclusion, 94% of patients reported any pain, 74.3% significant pain, and 26% severe pain. After 3 months, 18.8% of patients suffered from postherpetic neuralgia. At inclusion, 70.8% of patients had any itch, 39.2% significant itch, and 7.3% severe itch. The occurrence of pain increases costs and has a high impact on the quality of life, lowering EQ-5D scores by an average of 18%. In contrast, itch has little effect on the quality of life.

CONCLUSIONS

Pain and itch are highly prevalent months after HZ. Pain caused by HZ has a large impact on quality of life, burden of illness, impact on daily life, and health care costs for these patients. The impact of itch on quality of life is relatively small.

A systematic review and meta-analysis of risk factors for postherpetic neuralgia

Supplemental Digital Content is Available in the Text.

Patients with herpes zoster can develop persistent pain after rash healing, a complication known as postherpetic neuralgia. By preventing zoster through vaccination, the risk of this common complication is reduced. We searched MEDLINE and Embase for studies assessing risk factors for postherpetic neuralgia, with a view to informing vaccination policy. Nineteen prospective studies were identified. Meta-analysis showed significant increases in the risk of postherpetic neuralgia with clinical features of acute zoster including prodromal pain (summary rate ratio 2.29, 95% confidence interval: 1.42-3.69), severe acute pain (2.23, 1.71-2.92), severe rash (2.63, 1.89-3.66), and ophthalmic involvement (2.51, 1.29-4.86). Older age was significantly associated with postherpetic neuralgia; for individual studies, relative risk estimates per 10-year increase ranged from 1.22 to 3.11. Evidence for differences by gender was conflicting, with considerable between-study heterogeneity. A proportion of studies reported an increased risk of postherpetic neuralgia with severe immunosuppression (studies, n = 3/5) and diabetes mellitus (n = 1/4). Systemic lupus erythematosus, recent trauma, and personality disorder symptoms were associated with postherpetic neuralgia in single studies. No evidence of higher postherpetic neuralgia risk was found with depression (n = 4) or cancer (n = 5). Our review confirms a number of clinical features of acute zoster are risk factors for postherpetic neuralgia. It has also identified a range of possible vaccine-targetable risk factors for postherpetic neuralgia; yet aside from age-associated risks, evidence regarding risk factors to inform zoster vaccination policy is currently limited.

Relationships Among Adverse Events, Disease Characteristics, and Demographics in Treatment of Postherpetic Neuralgia With Gastroretentive Gabapentin

Objectives:

To characterize risk factors for occurrence of adverse events (AEs) and treatment discontinuations due to AEs for improving safety and tolerability of treatment of postherpetic neuralgia (PHN).

Methods:

Patients with PHN (n=556) received 1800 mg once-daily gastroretentive gabapentin (G-GR) in 2 phase 3 and 1 phase 4 study. Safety assessments included the incidence and severity of AEs and analysis of discontinuations due to AEs. Multivariable, logistic regression analyses examined predictors of AE reporting and discontinuations due to AEs.

Results:

In total, 53.2% of patients reported any AE, and 12.9% discontinued because of AEs. Both AE incidence and treatment discontinuations decreased rapidly during the 2-week titration to sustained, low levels. The probability to report any AE was 0.6 for females versus 0.4 for males, whereas there were no differences in probabilities for age (less than 75 vs. 75 y and older) and race (nonwhite vs. white). Consistent with this, only female sex was a significant (P=0.0006) predictor of AE reporting. Experiencing moderate (P≤0.0001) or severe (P=0.0006) AEs, but not patient demographics, was predictive of treatment discontinuations. The probability of discontinuation due to moderate AEs was 0.4 and 0.5 for severe AEs.

Discussion:

The tolerability of G-GR was not affected by patient age, but was affected by AE severity. Although being female was predictive of reporting AEs, it did not influence treatment discontinuation. Given that PHN is a disease for which the risk and duration of PHN increases with age and with being female, G-GR appears to be a well-suited treatment option for PHN.

Quantification of risk factors for postherpetic neuralgia in herpes zoster patients: A cohort study

OBJECTIVE

To investigate risk factors for postherpetic neuralgia, the neuropathic pain that commonly follows herpes zoster.

METHODS

Using primary care data from the Clinical Practice Research Datalink, we fitted multivariable logistic regression models to investigate potential risk factors for postherpetic neuralgia (defined as pain ≥90 days after zoster, based on diagnostic or prescription codes), including demographic characteristics, comorbidities, and characteristics of the acute zoster episode. We also assessed whether the effects were modified by antiviral use.

RESULTS

Of 119,413 zoster patients, 6,956 (5.8%) developed postherpetic neuralgia. Postherpetic neuralgia risk rose steeply with age, most sharply between 50 and 79 years (adjusted odds ratio [OR] for a 10-year increase, 1.70, 99% confidence interval 1.63-1.78). Postherpetic neuralgia risk was higher in women (6.3% vs 5.1% in men: OR 1.19, 1.10-1.27) and those with severely immunosuppressive conditions, including leukemia (13.7%: 2.07, 1.08-3.96) and lymphoma (12.7%: 2.45, 1.53-3.92); autoimmune conditions, including rheumatoid arthritis (9.1%: 1.20, 0.99-1.46); and other comorbidities, including asthma and diabetes. Current and ex-smokers, as well as underweight and obese individuals, were at increased risk of postherpetic neuralgia. Antiviral use was not associated with postherpetic neuralgia (OR 1.04, 0.97-1.11). However, the increased risk associated with severe immunosuppression appeared less pronounced in patients given antivirals.

CONCLUSIONS

Postherpetic neuralgia risk was increased for a number of patient characteristics and comorbidities, notably with age and among those with severe immunosuppression. As zoster vaccination is contraindicated for patients with severe immunosuppression, strategies to prevent zoster in these patients, which could include the new subunit zoster vaccine, are an increasing priority.

Efficacy of low dose gabapentin in acute herpes zoster for preventing postherpetic neuralgia: a prospective controlled study

Postherpetic neuralgia (PHN) is a sequela of herpes zoster that adversely affects quality of life seriously. The risk factors for PHN are well known but the effective interventions that reduce the incidence of PHN are less studied. The objective of this study is to evaluate the efficacy of treatment with gabapentin in patients with acute herpes zoster for preventing PHN. We performed a prospective randomized controlled study of 120 participants diagnosed with acute herpes zoster, aged 50 and over and complaining moderate to severe pain. All patients were treated with valacyclovir and acetaminophen. Half of the participants were assigned to the gabapentin group and received gabapentin 300 mg three times a day additionally. The intensity of pain at every visit and the incidence of PHN in both groups were measured. Total 52 and 49 patients in the gabapentin group and the control group, respectively, had completed 12 weeks of follow-up period. Although the incidence of PHN was higher in the control group, the difference was not statistically significant (6.1% vs. 3.8%, p = 0.67). Our results indicate that the use of low-dose gabapentin in acute herpes zoster seems not effective in the prevention of PHN.

Functional decline and herpes zoster in older people: an interplay of multiple factors

Herpes zoster is a frequent painful infectious disease whose incidence and severity increase with age. In older people, there is a strong bidirectional link between herpes zoster and functional decline, which refers to a decrement in ability to perform activities of daily living due to ageing and disabilities. However, the exact nature of such link remains poorly established. Based on the opinion from a multidisciplinary group of experts, we here propose a new model to account for the interplay between infection, somatic/psychiatric comorbidity, coping skills, polypharmacy, and age, which may account for the functional decline related to herpes zoster in older patients. This model integrates the risk of decompensation of underlying disease; the risk of pain becoming chronic (e.g. postherpetic neuralgia); the risk of herpes zoster non-pain complications; the detrimental impact of herpes zoster on quality of life, functioning, and mood; the therapeutic difficulties due to multimorbidity, polypharmacy, and ageing; and the role of stressful life events in the infection itself and comorbid depression. This model underlines the importance of early treatment, strengthening coping, and vaccine prevention.

Treatment of Postherpetic Neuralgia With Gastroretentive Gabapentin: Interaction of Patient Demographics, Disease Characteristics, and Efficacy Outcomes

To understand how patient demographics and patient-reported disease characteristics relate to successful management of postherpetic neuralgia (PHN), integrated data from phase 3 and phase 4 studies of patients with PHN (n = 546) who received once-daily gastroretentive gabapentin (G-GR, 1800 mg) were analyzed. There were widespread, networked, positive correlations among efficacy end points--pain qualities on the visual analog scale (VAS) and Brief Pain Inventory (BPI), measures of pain interference on the BPI, and Patient Global Impression of Change (PGIC)--most likely characterized by positive feedback loops, in which pain interferes with patient functioning, and poor functioning enhances pain. VAS scores at baseline or at week 2 were the strongest predictors of being "much" or "very much" improved on the PGIC; BPI sleep interference scores were the strongest predictors of percent changes in BPI pain qualities and in the average of BPI interference scores, whereas age, sex, and race were not important predictors. In addition to VAS, BPI sleep interference and PGIC assessments appeared to be key co-strategic factors important for successful treatment outcomes, and should be considered as co-primary end points in future clinical trials of PHN. This could improve detection of true positive efficacy responses and guide successful transition to real-world clinical practice.

PERSPECTIVE

This study describes complex relationships among measures of pain intensity, pain interference with daily activities, and demographics of patients with PHN treated with G-GR. Such comprehensive characterization provides important insight into how different variables contribute to successful treatment, and may lead to better management of neuropathic pain.

VZV skin-test reaction, but not antibody, is an important predictive factor for postherpetic neuralgia

BACKGROUND

The decline of cell-mediated immunity (CMI) is thought to be related to the risk of postherpetic neuralgia (PHN) as well as herpes zoster (HZ). However, the relationship between immunological condition and the incidence of PHN is still unclear.

OBJECTIVE

We conducted a large-scale prospective cohort study to clarify the relationship between immunological factors for varicella-zoster virus (VZV) and the incidence of PHN.

METHODS

We carried out a cohort study on VZV immunity in a population living on an island cluster, Shozu County in Japan, and examined the people who developed HZ during a follow-up period of 3 years, with a focus on the relationship between cell-mediated and humoral immunity and the incidence of PHN. A total of 12,522 people over the age of 50 were enrolled in this study, and 401 registrants were diagnosed with HZ, including 79 PHN cases. We evaluated anatomical location and severity of skin lesion, acute pain severity, presence or absence of abnormal sensations, CMI assessed by VZV skin test, and VZV-specific antibody titer measured by serological tests.

RESULTS

The incidence of PHN was significantly associated with a weak response to the VZV skin test, as well as facial or lumbosacral localization of skin rash, severe skin lesion, severe acute pain, and presence of abnormal sensations, but not related to VZV-specific antibody titer.

CONCLUSION

The incidence of PHN is significantly associated with the decline of VZV-specific CMI, but not related to VZV-specific humoral immunity.

Predictors of postherpetic neuralgia in patients with herpes zoster: a pooled analysis of prospective cohort studies from North and Latin America and Asia

OBJECTIVES

The most common complication of herpes zoster (HZ) is postherpetic neuralgia (PHN), a persistent pain that can substantially affect quality of life (QoL). This analysis aimed to evaluate predictors of PHN in HZ patients.

METHODS

A pooled analysis of prospective cohort studies of HZ patients aged ≥ 50 years from North America (Canada), Latin America (Brazil, Mexico, and Argentina), and Asia (Taiwan, South Korea, and Thailand) was performed. Patients within 14 days of rash onset were included. The incidence of PHN was defined as a worst pain score of ≥ 3, persisting/appearing at >90 days after rash onset. Socio-demographics, HZ disease characteristics, treatment, pain-related interference with activities of daily living, and health-related QoL were assessed.

RESULTS

Of 702 patients with HZ, 148 (21.1%) developed PHN. Similar risks of PHN were observed across geographic regions. On multivariate analysis, older age, greater severity of pain at rash onset, employment status, walking problems at enrollment, and pain interference affecting social relationships were significantly associated with the development of PHN.

CONCLUSIONS

In addition to older age and severe acute pain, this study suggests that impaired physical and social functioning from acute zoster pain may play a role in the development of PHN in this prospective cohort study of HZ patients from North and Latin America and Asia.

The humanistic, economic and societal burden of herpes zoster in Europe: a critical review

BACKGROUND

Herpes zoster (HZ) or "shingles" is common in persons aged 50 years or over. HZ is characterised by a painful dermatological rash which typically resolves in approximately one month. Persistent pain for months or years after rash onset, however, is a common complication of HZ; referred to as post-herpetic neuralgia (PHN). Both HZ and PHN have a significant impact on patients' lives, with considerable implications for healthcare systems and wider society. The aim of the present review is to provide comprehensive documentation and critical appraisal of published data concerning the humanistic, economic and societal burden of HZ in Europe.

METHODS

Systematic literature searches were conducted in Medline, EMBASE, PsycINFO, EconLit, HEED and CRD databases. Searches were conducted in July 2014 and restricted to articles published in the past 20 years. Articles were selected for full review by two independent researchers in accordance with predefined eligibility criteria.

RESULTS

From a review of 1619 abstracts, 53 eligible articles, were identified which reported data concerning healthcare resource use (n = 38), direct costs (n = 20), indirect costs (n = 16), total costs (n = 10) and impact on health-related quality of life (HRQoL) (n = 21). Findings highlight that PHN is associated with greater impairments in HRQoL and higher costs of management than HZ. For both HZ and PHN, pain severity is a significant predictor of impact on individuals, healthcare systems and society. While the incidence of HZ and PHN increase with age, age does not appear to be a key driver of overall costs for HZ and PHN. Specifically, while direct costs (e.g. GP, specialists, medications, hospitalisations) tend to be higher for older patients, indirect costs (e.g. work time missed) are higher for younger patients.

CONCLUSIONS

Available evidence highlights that HZ and PHN result in significant humanistic and economic burden for patients, healthcare systems and wider societies. A tendency to focus upon healthcare resource use and the direct costs of management at the expense of other impacts (e.g. informal caregivers and formal social care) may result in an underestimation of the true burden of HZ and PHN.

Varicella-zoster virus-derived major histocompatibility complex class I-restricted peptide affinity is a determining factor in the HLA risk profile for the development of postherpetic neuralgia

Postherpetic neuralgia (PHN) is the most common complication of herpes zoster and is typified by a lingering pain that can last months or years after the characteristic herpes zoster rash disappears. It is well known that there are risk factors for the development of PHN, such as its association with certain HLA alleles. In this study, previous HLA genotyping results were collected and subjected to a meta-analysis with increased statistical power. This work shows that the alleles HLA-A*33 and HLA-B*44 are significantly enriched in PHN patients, while HLA-A*02 and HLA-B*40 are significantly depleted. Prediction of the varicella-zoster virus (VZV) peptide affinity for these four HLA variants by using one in-house-developed and two existing state-of-the-art major histocompatibility complex (MHC) class I ligand prediction methods reveals that there is a great difference in their absolute and relative peptide binding repertoires. It was observed that HLA-A*02 displays a high affinity for an ∼7-fold-higher number of VZV peptides than HLA-B*44. Furthermore, after correction for HLA allele-specific limitations, the relative affinity of HLA-A*33 and HLA-B*44 for VZV peptides was found to be significantly lower than those of HLA-A*02 and HLA-B*40. In addition, HLA peptide affinity calculations indicate strong trends for VZV to avoid high-affinity peptides in some of its proteins, independent of the studied HLA allele.

IMPORTANCE

Varicella-zoster virus can cause two distinct diseases: chickenpox (varicella) and shingles (herpes zoster). Varicella is a common disease in young children, while herpes zoster is more frequent in older individuals. A common complication of herpes zoster is postherpetic neuralgia, a persistent and debilitating pain that can remain months up to years after the resolution of the rash. In this study, we show that the relative affinity of HLA variants associated with higher postherpetic neuralgia risk for varicella-zoster virus peptides is lower than that of variants with a lower risk. These results provide new insight into the development of postherpetic neuralgia and strongly support the hypothesis that one of its possible underlying causes is a suboptimal anti-VZV immune response due to weak HLA binding peptide affinity.

Systematic review of incidence and complications of herpes zoster: towards a global perspective

OBJECTIVE

The objective of this study was to characterise the incidence rates of herpes zoster (HZ), also known as shingles, and risk of complications across the world.

DESIGN

We systematically reviewed studies examining the incidence rates of HZ, temporal trends of HZ, the risk of complications including postherpetic neuralgia (PHN) and HZ-associated hospitalisation and mortality rates in the general population. The literature search was conducted using PubMed, EMBASE and the WHO library up to December 2013.

RESULTS

We included 130 studies conducted in 26 countries. The incidence rate of HZ ranged between 3 and 5/1000 person-years in North America, Europe and Asia-Pacific, based on studies using prospective surveillance, electronic medical record data or administrative data with medical record review. A temporal increase in the incidence of HZ was reported in the past several decades across seven countries, often occurring before the introduction of varicella vaccination programmes. The risk of developing PHN varied from 5% to more than 30%, depending on the type of study design, age distribution of study populations and definition. More than 30% of patients with PHN experienced persistent pain for more than 1 year. The risk of recurrence of HZ ranged from 1% to 6%, with long-term follow-up studies showing higher risk (5-6%). Hospitalisation rates ranged from 2 to 25/100 000 person-years, with higher rates among elderly populations.

CONCLUSIONS

HZ is a significant global health burden that is expected to increase as the population ages. Future research with rigorous methods is important.

Practical considerations in the pharmacological treatment of postherpetic neuralgia for the primary care provider

An estimated one million individuals in the US are diagnosed with herpes zoster (HZ; shingles) each year. Approximately 20% of these patients will develop postherpetic neuralgia (PHN), a complex HZ complication characterized by neuropathic pain isolated to the dermatome that was affected by the HZ virus. PHN is debilitating, altering physical function and quality of life, and commonly affects vulnerable populations, including the elderly and the immunocompromised. Despite the availability of an immunization for HZ prevention and several approved HZ treatments, the incidence of PHN is increasing. Furthermore, management of the neuropathic pain associated with PHN is often suboptimal, and the use of available therapeutics may be complicated by adverse effects and complex, burdensome treatment regimens, as well as by patients’ comorbidities and polypharmacy, which may lead to drug–drug interactions. Informed and comprehensive assessments of currently available pharmacological treatment options to achieve effective pain control in the primary care setting are needed. In this article, we discuss the situation in clinical practice, review currently recommended prevention and treatment options for PHN, and outline practical considerations for the management of this neuropathic pain syndrome, with a focus on optimal, individual-based treatment plans for use in the primary care setting.

Cost-effectiveness of vaccination against herpes zoster

Herpes zoster (HZ) is a common disease among elderly, which may develop into a severe pain syndrome labeled postherpetic neuralgia (PHN). A live-attenuated varicella zoster virus vaccine has been shown to be effective in reducing the incidence and burden of illness of HZ and PHN, providing the opportunity to prevent significant health-related and financial consequences of HZ. In this review, we summarize the available literature on cost-effectiveness of HZ vaccination and discuss critical parameters for cost-effectiveness results. A search in PubMed and EMBASE was performed to identify full cost-effectiveness studies published before April 2013. Fourteen cost-effectiveness studies were included, all performed in western countries. All studies evaluated cost-effectiveness among elderly above 50 years and used costs per quality-adjusted life year (QALY) gained as primary outcome. The vast majority of studies showed vaccination of 60- to 75-year-old individuals to be cost-effective, when duration of vaccine efficacy was longer than 10 years. Duration of vaccine efficacy, vaccine price, HZ incidence, HZ incidence and discount rates were influential to the incremental cost-effectiveness ratio (ICER). HZ vaccination may be a worthwhile intervention from a cost-effectiveness point of view. More extensive reporting on methodology and more detailed results of sensitivity analyses would be desirable to address uncertainty and to guarantee optimal comparability between studies, for example regarding model structure, discounting, vaccine characteristics and loss of quality of life due to HZ and PHN.

An overview of predictors for persistent neuropathic pain

Neuropathic pain (NP) is a pain arising as a direct consequence of a lesion or disease affecting the somatosensory system. A variety of factors associated with the development of persistent NP have been suggested. The goal of the present article is to provide an overview of current knowledge about prognostic factors for persistent NP. The International Classification of Functioning, Disability and Health model is used as a framework to categorize these predictors. Most reported predictors in the literature were found in the International Classification of Functioning, Disability and Health-category of personal factors, especially age and psychological factors, functions and structure, including sensory signs and symptoms. Predictors in the category of environmental factors, activities and participation were less frequently described.

Use of S-LANSS, a tool for screening neuropathic pain, for predicting postherpetic neuralgia in patients after acute herpes zoster events: a single-center, 12-month, prospective cohort study

Postherpetic neuralgia (PHN) is one of the most severe sequelae of herpes zoster events. Several risk factors have been reported for PHN, including old age, severe skin rash, and intense pain. This study therefore aims to evaluate the usefulness of the Self-completed Leeds Assessment of Neuropathic Symptoms and Signs pain scale (S-LANSS) in conjunction with previously reported risk factors for predicting PHN. A group of herpes zoster patients (N = 305) were included in the cohort study. Subjects were asked for their demographic information, clinical symptoms and signs, intensity of pain by visual analog scale (VAS), and S-LANSS. They were followed up in clinical visits or via telephone for 12 months. Nineteen patients (6.2%) suffered from PHN in this study. Using logistic regression, 3 risk factors for PHN were identified: age ≥70 years, high VAS scores, and high S-LANSS scores. Prediction of PHN using VAS (≥8) and S-LANSS (≥15) criteria achieved a sensitivity of 78.9% and specificity of 78.0%. Prediction of PHN in elderly patients (≥70 years), using the criteria of VAS (≥6) and S-LANSS (≥15) as well, achieved 100% sensitivity and 57.1% specificity. S-LANSS could be a useful prediction tool for PHN, particularly if combined with previously well-known risk factors and VAS.

PERSPECTIVE

Among acute herpes zoster patients, subjects with characteristics of neuropathic pain showed high frequency of PHN. The tools for screening neuropathic pain like S-LANSS could be helpful for predicting PHN and enabling early intervention of pain management.

Chloroquine diphosphate: a risk factor for herpes zoster in patients with dermatomyositis/polymyositis

OBJECTIVES

Herpes zoster has been widely described in the context of different systemic autoimmune diseases but not dermatomyositis/polymyositis. Therefore, we analyzed the prevalence, risk factors and herpes zoster outcomes in this population.

METHOD

A retrospective cohort study of herpes zoster infections in dermatomyositis/polymyositis patients was performed. The patients were followed at a tertiary center from 1991 to 2012. For the control group, each patient with herpes zoster was paired with two patients without herpes zoster. Patients were matched by gender and the type of myositis, age at myositis onset and disease duration.

RESULTS

Of 230 patients, 24 (10.4%) had a histories of herpes zoster (19 with dermatomyositis and five with polymyositis, two-thirds female). The mean age of the patients with herpes zoster was 44.6±16.8 years. No difference between the groups was found regarding cumulative clinical manifestations. Disease activity, autoantibody, muscle and leukogram parameters were also comparable between the groups. No differences in immunosuppressive (alone or in association with other immunosuppressive therapies) or glucocorticoid (current use, medium dose and cumulative dose in the last two months) therapies were found between patients with and without herpes zoster. However, a higher proportion of patients in the herpes zoster group received chloroquine diphosphate compared to the control group. All of the patients received acyclovir; 58.3% of patients had postherpetic neuralgia and no cases of recurrence were reported. Furthermore, individuals who were taking high prednisone doses at the time of the herpes zoster diagnosis had reduced levels of postherpetic neuralgia.

CONCLUSIONS

These data suggest that chloroquine diphosphate could predispose patients with dermatomyositis/polymyositis to developing herpes zoster, particularly women and dermatomyositis patients.

Predictive factors for postherpetic neuralgia using ordered logistic regression analysis

OBJECTIVES

To identify predictive factors for the occurrence of postherpetic neuralgia (PHN).

METHODS

The participants were 73 herpes zoster patients who had been treated at the pain clinic of our hospital between January 2008 and June 2010. Variables present at the initial visit were extracted from the clinical records for regression analysis of factors related to the occurrence of PHN. The following scores for response were used: 0=no PHN after 3 months; 1=PHN present after 3 months but absent after 6 months; and 2=PHN present after 6 months. Multivariate ordered logistic regression analysis was performed to identify the predictive factors for PHN.

RESULTS

Advanced age [odds ratio (OR)=2.740, confidence interval (CI)=1.110-6.761; P=0.0288] and deep pain (OR=4.244, CI=1.114-16.163; P=0.0341) at the initial visit to our outpatient pain clinic were found to be significant predictive factors for the occurrence of PHN. Diabetes mellitus (OR=3.075) and pain reduced by bathing (OR=3.389) also had high OR, although they were not significant.

DISCUSSION

Our study indicates that advanced age and deep pain at the initial visit are significant predictors for PHN. Our results are considered likely to contribute to the establishment of evidence-based medicine in the optimal treatment of PHN.

Vaccination against herpes zoster in developed countries: state of the evidence

Although progress has been made in the treatment of herpes zoster (HZ) and postherpetic neuralgia (PHN), available therapeutic options are only partially effective. Given evidence that a live-attenuated varicella-zoster-virus vaccine is effective at reducing the incidence of HZ, PHN and the burden of illness, policymakers and clinicians are being asked to make recommendations regarding the use of the zoster vaccine. In this report, we summarize the evidence regarding the: (1) burden of illness; (2) vaccine efficacy and safety; and (3) cost-effectiveness of vaccination, to assist evidence-based policy making and guide clinicians in their recommendations. First, there is general agreement that the overall burden of illness associated with HZ and PHN is substantial. Second, the safety and efficacy of the zoster vaccine at reducing the burden of illness due to HZ and the incidence of PHN have been clearly demonstrated in large placebo-controlled trials. However, uncertainty remains about the vaccine's duration of protection. Third, vaccination against HZ is likely to be cost-effective when the vaccine is given at approximately 65 y of age, if vaccine duration is longer than 10 y.

Herpes zoster ophthalmicus-induced oculomotor nerve palsy

Herpes zoster ophthalmicus (HZO) may cause a variety of ocular conditions including: dermatitis, corneal pseudo-dendrites, uveitis, retinitis, and cranial nerve palsies. Cranial nerve palsies caused by herpes zoster (HZ) are relatively uncommon clinical findings. Previous case reports have looked at this relationship, but the overall case studies are few. Other causes of nerve palsies typically need to be ruled out first with neuro-imaging and blood evaluations. However, when HZ is confirmed, treatment with oral antiviral therapy and/or oral corticosteroids along with monitoring the individual usually results in a self-limiting ophthalmoplegia that improves on its own over several months. We report a case of cranial nerve III palsy resulting from HZO.

Post-herpetic neuralgia

Background

In spite of the large body of evidence available in the literature, definition and treatment of Post-Herpetic Neuralgia (PHN) are still lacking a consistent and universally recognized standardization. Furthermore, many issues concerning diagnosis, prediction and prevention of PHN need to be clarified in view of recent contributions.

Objectives

To assess whether PHN may be better defined, predicted, treated and prevented in light of recent data, and whether available alternative or adjunctive therapies may improve pain relief in treatment recalcitrant PHN.

Methods

Systematic reviews, meta-analyses, randomized controlled trials, cohort studies and protocols were searched; the search sources included PubMed, Cochrane Library, NICE, and DARE. More than 130 papers were selected and evaluated.

Results

Diagnosis of PHN is essentially clinical, but it can be improved by resorting to the many tools available, including some practical and accessible questionnaires. Prediction of PHN can be now much more accurate, taking into consideration a few well validated clinical and anamnestic variables. Treatment of PHN is presently based on a well characterized array of drugs and drug associations, including, among others, tricyclic antidepressants, gabapentinoids, opioids and many topical formulations. It is still unsatisfactory, however, in a substantial proportion of patients, especially those with many comorbidities and intense pain at herpes zoster (HZ) presentation, so that this frequent complication of HZ still strongly impacts on the quality of life of affected patients.

Conclusion

Further efforts are needed to improve the management of PHN. Potentially relevant interventions may include early antiviral therapy of acute HZ, prevention of HZ by adult vaccination, as well as new therapeutic approaches for patients experiencing PHN.

Abnormal endogenous pain modulation is a shared characteristic of many chronic pain conditions

The intensity of acute and chronic pain depends on interactions between peripheral impulse input and CNS pain mechanisms, including facilitation and inhibition. Whereas tonic pain inhibition is a characteristic of most pain-free individuals, pain facilitation can be detected in many chronic pain patients. The capability to inhibit pain is normally distributed along a wide continuum in the general population and can be used to predict chronic pain. Accumulating evidence suggests that endogenous pain inhibition depends on activation of the prefrontal cortex, periaqueductal gray and rostral ventral medulla. Quantitative sensory test paradigms have been designed to acquire detailed information regarding each individual's endogenous pain inhibition and facilitation. Such tests include: temporal summation of pain, which is mostly used to assess facilitatory pain modulation by measuring the change in pain perception during a series of identical nociceptive stimuli; and conditioned pain modulation, which tests pain inhibition by utilizing two simultaneously applied painful stimuli (the 'pain inhibits pain' paradigm). Considerable indirect evidence seems to indicate that not only increased pain facilitation but also ineffective pain inhibition represents a predisposition for chronic pain. This view is supported by the fact that many chronic pain syndromes (e.g., fibromyalgia, temporomandibular joint disorder, irritable bowel syndrome, headache and chronic fatigue syndrome) are associated with hypersensitivity to painful stimuli and reduced endogenous pain inhibition. However, future prospective studies will be necessary to provide definitive evidence for this relationship. Such research would not only provide important information about mechanisms relevant to chronic pain but would also permit identification of individuals at high risk for future chronic pain.

Expert panel consensus recommendations for the pharmacological treatment of acute pain in the Middle East region

The findings of an expert panel convened to review critically how best to apply evidence-based guidelines for the treatment of acute pain in the Middle East region are presented. The panel recommended a three-step treatment protocol. Patients with mild-to-moderate levels of acute pain should be treated with paracetamol (step 1). If analgesia is insufficient after 1-2 days, a selective cyclo-oxygenase-2 inhibitor or, if gastrointestinal safety and bleeding risk are not an issue, a non-specific nonsteroidal anti-inflammatory drug, should be used (step 2). If analgesia remains inadequate, treatment with tramadol, or paracetamol plus codeine/tramadol is recommended (step 3). Patients reporting severe pain should be referred to a pain clinic or specialist for opioid analgesic treatment. Measures of pain and functioning that have been validated in Arabic, with culturally appropriate and easy to understand descriptors, should be used. Early and aggressive acute pain management is important to reduce the risk of pain becoming chronic, especially in the presence of neuropathic features.

Employment related productivity loss associated with herpes zoster and postherpetic neuralgia: a 6-month prospective study

We conducted a prospective multi-center study to assess productivity loss associated with herpes zoster (HZ) and postherpetic neuralgia (PHN). From 10/2005 to 07/2006, we recruited immunocompetent subjects aged ≥50 years with HZ within 14 days of rash onset across Canada. Of the 249 patients recruited, 88 were employed. Data on employment status, absences from work, reasons for absence and effectiveness at work were documented at recruitment, 7-14-21-30-60-90-120-150 and 180 days later. The majority (64%) of employed subjects missed work because of HZ and 76% reported decreased effectiveness at work (i.e. presenteeism) because of HZ/PHN. Mean hours of absenteeism and presenteeism per working individual were 27 and 34 h, respectively. Pain severity and duration were associated with greater productivity loss. These results provide new information about the burden of HZ and PHN, which is useful for public health planning and cost-effectiveness analyses of HZ vaccination among individuals of working age.

The health and economic burden of chickenpox and herpes zoster in Belgium

Varicella-zoster virus causes chickenpox (CP) and after reactivation herpes zoster (HZ). Vaccines are available against both diseases warranting an assessment of the pre-vaccination burden of disease. We collected data from relevant Belgian databases and performed five surveys of CP and HZ patients. The rates at which a general practitioner is visited at least once for CP and HZ are 346 and 378/100 000 person-years, respectively. The average CP and HZ hospitalization rates are 5·3 and 14·2/100 000 person-years respectively. The direct medical cost for HZ is about twice as large as the direct medical cost for CP. The quality-adjusted life years lost for ambulatory CP patients consulting a physician is more than double that of those not consulting a physician (0·010 vs. 0·004). In conclusion, both diseases cause a substantial burden in Belgium.

Possible association of lower rate of postherpetic neuralgia in patients on anti-tumor necrosis factor-α

Recently, a study of patients with rheumatoid arthritis who developed herpes zoster while taking a tumor necrosis factor (TNF)-α inhibitor reported a decreased incidence of postherpetic neuralgia. The objective of this study was to investigate whether patients on TNF-α inhibitors who developed herpes zoster have a lower incidence of subsequent development of postherpetic neuralgia. A retrospective review of herpes zoster patients on TNF-α inhibitors (infliximab, etanercept, or adalimumab) was conducted in 12 dermatology clinics. Medical records of such patients were reviewed thoroughly to confirm herpes zoster and TNF-α inhibitors and any subsequent development of postherpetic neuralgia (pain score ≥ 3 out of 10 after 90 days of shingles onset) was noted. A total of 206 cases were reviewed, of which only 2 cases (<1%) developed postherpetic neuralgia, a considerably lower incidence rate than noted in the literature. Increasing age is a known risk factor in the development of postherpetic neuralgia. However, of the 58 (28.1%) cases ≥ 70 years of age, only 1 patient (1.7%) developed neuralgia compared to approximately 50% of patients who develop postherpetic neuralgia in this age group as reported in the literature. Treatment with TNF-α inhibitors may be associated with a lower incidence of postherpetic neuralgia but further prospective large-scale studies are needed to confirm this data.

Measuring the burden of herpes zoster and post herpetic neuralgia within primary care in rural Crete, Greece

Background

Research has indicated that general practitioners (GPs) have good clinical judgment in regards to diagnosing and managing herpes zoster (HZ) within clinical practice in a country with limited resources for primary care and general practice. The objective of the current study was to assess the burden of HZ and post herpetic neuralgia (PHN) within rural general practices in Crete, Greece.

Methods

The current study took place within a rural setting in Crete, Greece during the period of November 2007 to November 2009 within the catchment area in which the Cretan Rural Practice-based Research Network is operating. In total 19 GP's from 14 health care units in rural Crete were invited to participate, covering a total turnover patient population of approximately 25, 000 subjects. For the purpose of this study an electronic record database was constructed and used as the main tool for monitoring HZ and PHN incidence. Stress related data was also collected with the use of the Short Anxiety Screening Test (SAST).

Results

The crude incidence rate of HZ was 1.4/1000 patients/year throughout the entire network of health centers and satellite practices, while among satellite practices alone it was calculated at 1.3/1000 patients/year. Additionally, the standardised incidence density within satellite practices was calculated at 1.6/1000 patients/year. In regards to the stress associated with HZ and PHN, the latter were found to have lower levels of anxiety, as assessed through the SAST score (17.4 ± 3.9 vs. 21.1 ± 5.7; p = 0.029).

Conclusions

The implementation of an electronic surveillance system was feasible so as to measure the burden of HZ and PHN within the rural general practice setting in Crete.

Patient perspective on herpes zoster and its complications: an observational prospective study in patients aged over 50 years in general practice

Understanding the effect of herpes zoster and zoster-related pain should inform care to improve health-related quality of life in elderly patients. A 12-month, longitudinal, prospective, multicenter observational study conducted in primary care in France enrolled patients aged ≥ 50 years with acute eruptive herpes zoster. Patient-reported zoster-related pain was assessed by validated questionnaires (Douleur Neuropathique en 4 Questions [DN4], Zoster Brief Pain Inventory [ZBPI], and Neuropathic Pain Symptom Inventory [NPSI]) on days 0 and 15, and at months 1, 3, 6, 9, and 12. Health-related quality of life was assessed by the 12-item short-form health survey (SF-12) and the Hospital Anxiety and Depression scale on day 0 and at months 3, 6, and 12. Of 1358 patients included, 1032 completed follow-up. Mean ± standard deviation age was 67.7 ± 10.7 (range, 50-95) years; 62.2% were women. Most patients (94.1%) were prescribed antiviral drugs. The prevalence of zoster-related pain on day 0 and at months 3, 6, 9, and 12 was 79.6%, 11.6%, 8.5%, 7.4%, and 6.0%, respectively. Patients with persistent pain had lower scores on the physical and mental component summaries of the SF-12 and the ZBPI interference score than those without pain. By logistic regression analysis, main predictive factors on day 0 for postherpetic neuralgia at month 3 were age, male sex, ZBPI interference score, Physical Component Summary score of the SF-12, and neuropathic quality of pain (DN4 score ≥ 4). Despite early diagnosis and treatment with antiviral agents, many patients with herpes zoster experience persistent pain and marked long-term reduction in health-related quality of life.

Predictors of postherpetic neuralgia among patients with herpes zoster: a prospective study

Postherpetic neuralgia (PHN) is the most common complication of herpes zoster (HZ). The main objectives of this study were to: 1) estimate the severity and duration of PHN; and 2) identify the predictors of PHN. From October, 2005 to July, 2006, 261 outpatients with HZ, aged ≥ 50, were recruited within 14 days of rash onset during the routine clinical practice of 83 physicians across Canada. Physicians documented HZ characteristics, treatments, general health, functional, and immune status. HZ pain was measured at recruitment and on days 7, 14, 21, 30, 60, 90, 120, 150, and 180 following recruitment. PHN was defined as a worst pain ≥ 3 persisting or appearing more than 90 days after rash onset. Predictors of PHN were obtained by hierarchical log-binomial regression. Twenty-two percent of 249 immunocompetent subjects with HZ developed PHN. Median duration of PHN was 77 days. Independent predictors of PHN included: older age, limitation in performing usual activities prior to HZ, and pain severity at recruitment. This study confirms that older age and greater acute pain severity are predictors of PHN, while functional status emerges as a novel independent predictor of PHN that deserves further exploration. These findings will contribute to optimal use of the HZ vaccine and testing of new therapies that might prevent PHN.

PERSPECTIVE

This study confirmed that older age and greater acute pain severity are robust predictors of PHN, whereas functional status emerged as a novel predictor. Despite the high proportion of subjects treated with antivirals, the burden of PHN remains considerable, suggesting that prevention and additional early interventions are needed to reduce the burden of HZ.