Predictors of pain intensity and persistence in a prospective Italian cohort of patients with herpes zoster: relevance of smoking, trauma and antiviral therapy

The Incidence of Herpes Zoster Complications: A Systematic Literature Review

INTRODUCTION

The objective of this work was to summarize the incidence of herpes zoster (HZ) complications in different populations.

METHODS

Systematic literature review of PubMed, Embase, and Virtual Health Library records between January 1, 2002 and October 20, 2022 using search strings for HZ, complications, and frequency measurements.

RESULTS

The review included 124 studies, most conducted in the general population (n = 93) and on individuals with comorbidities (n = 41) ≥ 18 years of age. Most studies were conducted in Europe (n = 44), Asia (n = 40), and North America (n = 36). Postherpetic neuralgia (PHN) was the most studied neurological complication. Variable relative PHN incidence was found in the general population (2.6-46.7%) or based on diagnosis: immunocompromised (3.9-33.8%), depression (0-50%), and human immunodeficiency virus (HIV) (6.1-40.2%). High incidence rates were observed in hematological malignancies (HM) and solid organ malignancies (132.5 and 93.7 per 1000 person-years, respectively). Ocular complications were frequently reported with herpes zoster ophthalmicus (HZO). The relative incidence (incidence rate) of HZO in the general population was reported as 1.4-15.9% (0.31-0.35 per 1000 person-years). High relative incidence was observed in HIV (up to 10.1%) and HM (3.2-11.3%). Disseminated HZ was the most frequently reported cutaneous complication. The relative incidence of disseminated HZ was 0.3-8.2% in the general population, 0-0.5% in the immunocompetent, and 0-20.6% in patients with comorbidities. High relative incidence was reported in HM and solid organ transplant (up to 19.3% and 14.8%, respectively).

DISCUSSION

Most reported complications were neurological (n = 110), ocular (n = 48), and cutaneous (n = 38). Few studies stratified complications by age or gender (or both). Incidence appeared higher in select immunocompromised populations. Higher incidence was associated with older age in several studies; the general association with gender was unclear.

CONCLUSIONS

Variable incidence of HZ complications was reported by population subgroup. Further research is required to quantitatively analyze incidence by age, gender, and location.

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.

Epidemiology of neuropathic pain: an analysis of prevalence and associated factors in UK Biobank

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An analysis of UK Biobank participants who completed a detailed pain questionnaire identified factors associated with neuropathic pain (NeuP) vs no chronic pain and non-NeuP and estimated the prevalence of NeuP.

Introduction:

Previous epidemiological studies of neuropathic pain have reported a range of prevalences and factors associated with the disorder.

Objectives:

This study aimed to verify these characteristics in a large UK cohort.

Methods:

A cross-sectional analysis was conducted of 148,828 UK Biobank participants who completed a detailed questionnaire on chronic pain. The Douleur Neuropathique en Quatre Questions (DN4) was used to distinguish between neuropathic pain (NeuP) and non-neuropathic pain (non-NeuP) in participants with pain of at least 3 months' duration. Participants were also identified with less than 3 months' pain or without pain (NoCP). Multivariable regression was used to identify factors associated with NeuP compared with non-NeuP and NoCP, respectively.

Results:

Chronic pain was present in 76,095 participants (51.1%). The overall prevalence of NeuP was 9.2%. Neuropathic pain was significantly associated with worse health-related quality of life, having a manual or personal service type occupation, and younger age compared with NoCP. As expected, NeuP was associated with diabetes and neuropathy, but also other pains (pelvic, postsurgical, and migraine) and musculoskeletal disorders (rheumatoid arthritis, osteoarthritis, and fibromyalgia). In addition, NeuP was associated with pain in the limbs and greater pain intensity and higher body mass index compared with non-NeuP. Female sex was associated with NeuP when compared with NoCP, whereas male sex was associated with NeuP when compared with non-NeuP.

Conclusion:

This is the largest epidemiological study of neuropathic pain to date. The results confirm that the disorder is common in a population of middle- to older-aged people with mixed aetiologies and is associated with a higher health impact than non-neuropathic pain.

Development and external validation of multivariable risk models to predict incident and resolved neuropathic pain: a DOLORisk Dundee study

Neuropathic pain is difficult to treat, and an understanding of the risk factors for its onset and resolution is warranted. This study aimed to develop and externally validate two clinical risk models to predict onset and resolution of chronic neuropathic pain. Participants of Generation Scotland: Scottish Family Health Study (GS; general Scottish population; n = 20,221) and Genetic of Diabetes Audit and Research in Tayside Scotland (GoDARTS; n = 5236) were sent a questionnaire on neuropathic pain and followed- -up 18 months later. Chronic neuropathic pain was defined using DN4 scores (≥ 3/7) and pain for 3 months or more. The models were developed in GS using logistic regression with backward elimination based on the Akaike information criterion. External validation was conducted in GoDARTS and assessed model discrimination (ROC and Precision-Recall curves), calibration and clinical utility (decision curve analysis [DCA]). Analysis revealed incidences of neuropathic pain onset (6.0% in GS [236/3903] and 10.7% in GoDARTS [61/571]) and resolution (42.6% in GS [230/540] and 23.7% in GoDARTS [56/236]). Psychosocial and lifestyle factors were included in both onset and resolved prediction models. In GoDARTS, these models showed adequate discrimination (ROC = 0.636 and 0.699), but there was evidence of miscalibration (Intercept = - 0.511 and - 0.424; slope = 0.623 and 0.999). The DCA indicated that the models would provide clinical benefit over a range of possible risk thresholds. To our knowledge, these are the first externally validated risk models for neuropathic pain. The findings are of interest to patients and clinicians in the community, who may take preventative or remedial measures.

Consensus statement on smoking cessation in patients with pain

Smoking is closely associated with the development of various cancers and tobacco-related illnesses such as cardiovascular and respiratory disorders. However, data are scarce on the relationship between smoking and both acute and chronic pain. In addition to nicotine, tobacco smoke contains more than 4000 different compounds. Although nicotine is not the sole cause of smoking-induced diseases, it plays a critical role in pain-related pathophysiology. Despite the acute analgesic effects of nicotine, long-term exposure leads to tolerance and increased pain sensitivity due to nicotinic acetylcholine receptor desensitization and neuronal plastic changes. The purpose of smoking cessation interventions in smoking patients with pain is primarily not only to reduce their pain and associated limitations in activities of daily living, but also to improve the outcomes of underlying pain-causing conditions and reduce the risks of tobacco-related disorders. This statement aims to summarize the available evidence on the impact of smoking on pain and to inform medical professionals of the significance of smoking cessation in patients with pain.

miR-338-5p Levels and Cigarette Smoking are Associated With Neuropathic Pain Severity in Individuals With Spinal Cord Injury: Preliminary Findings From a Genome-Wide microRNA Expression Profiling Screen

OBJECTIVE

To identify microRNA biomarkers and clinical factors associated with neuropathic pain after spinal cord injury.

DESIGN

Cross-sectional, secondary analysis of baseline data collected from ongoing clinical studies. Using a genome-wide microRNA screening approach, we studied differential microRNA expression in serum from 43 adults with spinal cord injury enrolled in ongoing clinical studies. Least squares regression was used to identify associations between microRNA expression, clinical factors, and neuropathic pain severity.

SETTING

Community-dwelling individuals with spinal cord injury.

PARTICIPANTS

Participants (N=43) were at least 18 years old with spinal cord injury, with 28 reporting neuropathic pain and 15 reporting no neuropathic pain.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Pain presence, type, and intensity were assessed with the International Spinal Cord Injury Pain Basic Data Set. Serum microRNA normalized deep sequencing counts were quantified from blood samples. Participant demographic factors, injury characteristics, medication use, and health habits were collected via questionnaire.

RESULTS

miR-338-5p expression and history of cigarette smoking were associated with and explained 37% of the variance in neuropathic pain severity (R2=0.37, F2,18=5.31, P=.02) independent of other clinical factors. No association was identified between miR-338-5p levels and nociceptive pain severity.

CONCLUSIONS

Our findings suggest that miR-338-5p and cigarette smoking may both play a role in the development or maintenance of neuropathic pain after spinal cord injury. While additional work is needed to confirm these findings, validated target analysis suggests a neuroprotective role of miR-338-5p in modulating neuroinflammation and neuronal apoptosis and that its downregulation may result in maladaptive neuroplastic mechanisms contributing to neuropathic pain after spinal cord injury.

Assessment of Serum Vitamin D Levels in the serum of Patients with Postherpetic neuralgia and its correlation to pain severity: A cross-sectional comparative study

INTRODUCTION

Vitamin D is an essential micronutrient for the maintenance of many functions in the human body. Postherpetic neuralgia (PHN) is caused by the reactivation of the latent varicella-zoster virus (VZV) in the neurons. This study aims to assess the serum vitamin D level in patients with PHN and to correlate the level of vitamin D with pain severity.

METHODS AND MATERIALS

A hospital-based cross-sectional comparative study was conducted in the period from April 2019 to January 2021. One hundred and sixty-two individuals, matched for age and gender, divided into cases and controls (81 for each). Serum levels of 25(OH)D were measured for cases and controls. Demographic data were taken, and then the diagnosis of neuropathic pain in cases was established using the Douleur Neuropathique 4 (DN4) questionnaire.

RESULTS

We included 39 (52%) males in the PHN group and 36 (48%) in the control group. There was no significant difference between groups regarding age, marital status, smoking and BMI. The duration of pain in our study had a mean of 7.6 ± 3.6 months. We found the DN4 score for the pain to be negatively associated with vitamin D levels (Pearson's correlation coefficient: -0.511, P = .000). The levels of vitamin D were moderately associated with pain duration (Pearson's correlation: -0.466, P = .000).

CONCLUSION

PHN patients had a high prevalence of vitamin D deficiency and those who had vitamin D deficiency were older and had higher degrees of pain for a longer duration. In PHN patients, vitamin D deficiency was moderately associated with increased severity and duration of pain.

Smoking Is Associated with Pain in All Body Regions, with Greatest Influence on Spinal Pain

OBJECTIVE

Examine the interrelationship between smoking and pain in the US population.

DESIGN

A cross-sectional population-based study.

SETTING

Nationwide survey.

METHODS

Comprehensive pain reports categorically defined as head, spine, trunk, and limb pain; smoking history; demographics; medical history from a total of 2,307 subjects from the 2003-2004 National Health and Nutrition Examination Survey obtained from the Centers for Disease Control were analyzed. Unpaired t tests were used to analyze independent continuous variables, and chi-square tests were used to analyze categorical variables between smoker and nonsmoker groups. Weighted multivariate logistic regression analyses determined the association of current smoking with the presence of pain in various body regions.

RESULTS

Smoking is most strongly associated with spine pain (odds ratio [OR] = 2.89, 95% confidence interval [CI] = 2.21-3.77), followed by headache (OR = 2.47, 95% CI = 1.73-3.53), trunk pain (OR = 2.17, 95% CI = 1.45-2.74), and limb pain (OR = 1.99, 95% CI = 1.45-2.73).

CONCLUSIONS

Current smoking is associated with pain in every region of the body. This association is strongest for spine and head pain. Given that pain is a strong motivator and that current smoking was associated with pain in all body regions, we recommend that these results be used to further raise public awareness about the potential harms of smoking.

Plasma Vitamin C Concentrations Were Negatively Associated with Tingling, Prickling or Pins and Needles Sensation in Patients with Postherpetic Neuralgia

Vitamin C deficiency increases the risk of postherpetic neuralgia (PHN). In this cross-sectional study, the relationships among plasma vitamin C concentrations, pain and Leeds assessment of neuropathic symptoms and signs (LANSS) items were investigated during their first pain clinic visit of 120 PHN patients. The factors associated with vitamin C deficiency were determined. Independent predictors of vitamin C deficiency were presented as adjusted odds ratios (AOR) and 95% confidence intervals (CI). The patients had a high prevalence (52.5%) of vitamin C deficiency. Their plasma vitamin C concentrations were negatively associated with spontaneous pain and tingling, prickling or pins and needles sensation according to the LANSS questionnaire. Based on the receiver operator characteristic curve, the cutoffs for plasma vitamin C to predict moderate-to-severe and severe symptoms of sharp sensation were <7.05 and <5.68 mg/L, respectively. By comparison, the patients well-nourished with vitamin C had lower incidences of sharp sensations, sharp pain, and reddish skin. Multivariate analyses revealed that vitamin C deficiency was associated with the low intake of fruit/vegetables (AOR 2.66, 95% CI 1.09–6.48, p = 0.032), peptic ulcer disease (AOR 3.25, 95% CI 1.28–8.28, p = 0.014), and smoking (AOR 3.60, 95% CI 1.33–9.77, p = 0.010). Future studies are needed to substantiate these findings.

Pregabalin-associated stuttering and frequent blepharospasm: case report and review

Herpes zoster is an acute, painful, herpes skin disease caused by varicella-zoster virus, which may cause viral meningitis. Pregabalin has been shown to be efficacious in the treatment of pain in patients with herpes zoster. However, it has the side effects of neurotoxicity. We describe a 68-year-old female patient with herpes zoster, and she was treated with pregabalin. The patient presented with stuttering and frequent blepharospasm after 3 days of pregabalin treatment. Pregabalin was discontinued, the symptoms of stuttering and frequent blepharospasm completely resolved without any special treatment after one week. In this case, the etiology of stuttering and frequent blepharospasm may be related to pregabalin. Clinicians should be alert to the rare symptoms associated with the use of pregabalin.

Graphical abstract

Tobacco Use and Orofacial Pain: A Meta-analysis

Introduction

The relationship between smoking and general body ache has been shown to be bidirectional. The specific association between tobacco consumption and orofacial pain remains unclear, however.

Aim and Methods

The aim of this systematic review was to explore the association between pain related to diseases of the oral cavity and use of tobacco. A systematic search of PubMed, Embase, Web of Science, and Cochrane databases was carried out in September 2019. Tobacco exposure was included irrespective of the method of consumption (smokeless and smoked tobacco), and frequency of the habit. The outcome was defined as clinically diagnosed or self-reported pain in the orofacial region, with no limitation in the duration of the condition or the site of the pain.

Results

Altogether, eight studies were selected, with three of them demonstrating good methodology and none of them being of poor quality. Meta-analysis of six studies showed that orofacial pain was significantly worse in tobacco (smoked and smokeless) users (odds ratio [OR] = 3.55, 95% confidence interval [CI]: 1.92, 6.58) in comparison to nonusers. Subgroup analysis showed that the odds of orofacial pain was three times (OR = 3.13, 95% CI: 1.16, 8.46) higher among smokers, but was not associated with smokeless tobacco.

Conclusions

The odds of experiencing orofacial pain among patients with oral diseases increase for patients who are also smokers. The findings could help dentists and other health specialists more effectively manage patients with orofacial pain who are tobacco consumers.

Implications

This study shows that the odds of orofacial pain among patients with oral diseases increase for patients who are smokers. The results are a significant contribution to the literature because, while the relationship between smoking and general body ache has been shown to be bidirectional, the specific association between tobacco use and orofacial pain warranted further study. The findings could help dentists and other specialists more effectively manage patients with orofacial pain who are also tobacco consumers.

Do varicella vaccination programs change the epidemiology of herpes zoster? A comprehensive review, with focus on the United States

Introduction: Policy-makers in many countries have been wary of introducing varicella vaccination programs because of concerns that reduced exposures to varicella-zoster virus could increase herpes zoster (HZ) incidence. The U.S. introduced varicella vaccination in 1996 and has empiric evidence regarding this concern. Areas covered: This comprehensive review provides background emphasizing the epidemiology of varicella and of HZ in the U.S. before and after the introduction of their respective vaccines. The epidemiology is complex, and interpretation is complicated by methodologic challenges, by unexplained increases in age-specific HZ incidence that preceded varicella vaccination, and by introduction of vaccines for prevention of HZ. Nonetheless, observations from studies using different platforms and designs have yielded consistent findings, suggesting they are robust. Expert opinion: There has been no evidence that the U.S. varicella vaccination program increased HZ incidence in the general adult population over baseline trends. Furthermore, HZ incidence in children is declining. The U.S. experience can inform the development of new generations of models to predict HZ trends. More importantly, it provides reassurance for countries considering varicella vaccination that an effective program can reduce varicella morbidity and mortality while reducing the likelihood of HZ among children, and potentially, over time, across the entire population.

The Epidemiology of Herpes Zoster and Postherpetic Neuralgia in China: Results from a Cross-Sectional Study

Introduction

Few studies have examined the epidemiology of herpes zoster (HZ) and postherpetic neuralgia (PHN) in China. The aim of this study was to estimate the prevalence of HZ and PHN in China, and to examine the clinical characteristics of patients identified with PHN.

Methods

This was a cross-sectional study conducted in 24 hospitals in seven cities in China. Prevalence of HZ and PHN was determined by physician (n = 100) chart review of patients (n = 36,170) aged ≥ 40 years seeking medical care over a 30- to 60-day period. The health history of patients identified with PHN was obtained and included time since diagnosis of HZ or PHN, time since onset of PHN-related pain, and the methods used for diagnosing HZ and PHN.

Results

The prevalence rates of HZ and PHN were 7.7% [95% confidence interval (CI) 7.5–8.0] and 2.3% (95% CI 2.2–2.5), respectively. Of patients with HZ, 29.8% developed PHN. Rates of HZ and PHN increased with age and were highest in patients aged ≥ 70 years (10.6% and 4.1%, respectively). The majority of patients with PHN were diagnosed with HZ (80.9%) and PHN (83.8%) for < 1 year, and had experienced PHN-related pain for < 1 year (80.5%). Patient description and clinical examination were most commonly used to diagnose HZ and PHN.

Conclusion

These results provide current estimates of the prevalence of HZ and PHN in the general adult population in urban China. These rates are similar to previously reported rates in China and worldwide, and highlight the global nature of HZ and PHN.

Funding

Pfizer Inc.

An Evaluation of Efficacy and Safety of Commonly Prescribed Drugs and Effect of These Drugs on Quality of Sleep in Patients Suffering From Zoster-Associated Pain

This observational, prospective, single-center study was conducted to evaluate the efficacy and safety of commonly prescribed drugs for zoster-associated pain and their impact on quality of sleep at a tertiary care hospital in western India. Patients ≥18 years of age, newly diagnosed with zoster-associated pain were evaluated on days 0, 7, 14, 30, 60, 90, 120, 150, and 180 or until resolution of pain, whichever was earlier, using the Wong Baker FACES Pain Rating Scale, Neuropathic Pain Scale, and Insomnia Severity Index for intensity of pain, quality of pain, and quality of sleep, respectively. A total of 78 patients (46.0 [16.3] years) completed the study. They received nonsteroidal anti-inflammatory drugs (65), gabapentin (30), amitriptyline (27), and amitriptyline + gabapentin (21) for mean durations of 7.7 (3.0), 89.2 (7.2), 107.6 (46.3), and 104.5 (46) days, respectively. Improvement in the Wong Baker FACES Pain Rating Scale and Neuropathic Pain Scale score was similar among treatment groups except for a greater fall in Wong Baker FACES Pain Rating Scale score at days 7 and 120 and that in deep pain score at day 7 in combination treatment group vs the amitriptyline group. Clinically significant insomnia was detected in 35 patients at baseline and demonstrated progressive and similar improvement among groups. Treatment modification was required in 20 patients. Zoster-associated pain resolved in 69 patients. Nine adverse drug reactions, mostly mild, nonserious, and nonpreventable, were reported. To conclude, drugs commonly used for zoster-associated pain are effective and well tolerated. These have a similar effect on pain and quality of sleep, except for a possible greater effect of combination treatment in the early phase of intense and deep pain.

Letter to the editor regarding "The role of age-sex interaction in the development of post-herpetic neuralgia"

The objective of the study was to evaluate the role of age and sex and their combined effect in the development of post-herpetic neuralgia (PHN) in a large population-based study, in order to confirm the results published previously by Amicizia et al. Data were extracted from population and healthcare databases from the Valencia Region (2009-2014). Logistic regressions were implemented to estimate the effect of increasing age on the probability of developing PHN stratified by sex. From a cohort of 2,289,485 subjects ≥ 50 years, 87,086 cases of HZ were registered and 13,658 (15.7%) of them developed PHN. In our population, PHN cases were more common in women and rose with increasing age independently of the sex.

Biological mechanism of post-herpetic neuralgia: Evidence from multiple patho-psychophysiological measures

BACKGROUND

Post-herpetic neuralgia (PHN), which develops after the resolution of a herpes zoster eruption, is an exceptionally drug-resistant neuropathic pain. The unsatisfactory management of PHN partly results from the difficulty in dissecting out its contributing factors due to the complexity of PHN mechanism.

METHODS

Here, to elaborate our understanding of the PHN mechanism and to establish a basis for effective therapeutic strategies, we comprehensively investigated the contributions of multiple factors to PHN severity.

RESULTS

Based on the comparison of somatosensory detection thresholds (C, Aδ and Aβ fibre thresholds) between affected and unaffected sides, 16 PHN patients with significant sensory deficits and 13 PHN patients without significant sensory deficits were identified and assigned to different groups. The different extents of lesions in the nociceptive system between patients with and without sensory deficits were confirmed using laser-evoked brain responses. Moreover, patients with sensory deficits had more severe pain and psychological disorders, e.g. anxiety and depression. Importantly, chronic pain severity was significantly influenced by various psychophysiological factors (sleep disturbances, psychological disorders and hypothalamic-pituitary-adrenal axis dysfunction) for patients with sensory deficits.

CONCLUSIONS

Our findings demonstrated the contribution of multiple patho-psychophysiological factors to PHN severity, which could help establish a basis for the development of a rational, patient-centred therapeutic strategy.

SIGNIFICANCE

This study revealed the contribution of multiple patho-psychophysiological factors to PHN severity, which expanded our understanding of the underlying PHN mechanism, and helped develop a rational, patient-centred therapeutic strategy targeting towards the corresponding etiology and psychophysiological disorders for individual patient.

Initial Presentation Sites as Predictors of Herpes Zoster Complications: A Nationwide Cohort Study

Herpes zoster (HZ) is associated with complications such as postherpetic neuralgia (PHN) and HZ ophthalmicus (HZO). However, few studies have focused on identifying patients having a high risk of PHN and HZO according to the initial presentation sites. The current study investigated these factors in a nationwide population-based cohort derived from Taiwan’s Longitudinal Health Insurance Database. The results indicate that the initial presentation sites can predict the complication site of HZ. In this study, elderly patients were found to be more susceptible to HZ and were the first to present with neurological signs (HZN). Furthermore, compared with patients with HZO and other signs (HZT), those with HZN had a higher comorbidity risk. Patients with HZN showed a significantly higher visceral complication risk than did those with HZO (adjusted hazard ratio [HR] = 1.47, 95% confidence interval [CI] = 1.27–1.71). In addition, patients with HZT showed lower risks of ocular and neurological complications than did those with HZN after stratification by age and sex (adjusted HR = 0.46, 95% CI = 0.31–0.68 and HR = 0.73, 95% CI = 0.59–0.91, respectively).

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.

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.

Self-reported herpes zoster, pain, and health care seeking in the Health and Retirement Study: implications for interpretation of health care-based studies

Purpose

To describe self-reported herpes zoster (HZ) and explore factors that could impact interpretation of results from health care–based HZ studies.

Methods

We performed logistic regression using data from the 2008 Health and Retirement Study (HRS) to evaluate risk factors for having a history of HZ and experiencing severe HZ pain, and predictors for seeking health care for HZ.

Results

Among 14,564 respondents aged ≥55 years, women were more likely than men to report a history of HZ (15.7% vs. 11.6%, P < .01). Blacks (6.4% vs. 14.7% in whites, P < .01) and respondents with less than a high school diploma (12.2% vs.14.2% in respondents with at least a high school diploma, P = .01) were less likely to report a history of HZ. Women, blacks, Hispanics, and those with less than a high school diploma were more likely to report severe HZ pain. Most (91.1%) respondents sought health care for HZ; Hispanics (64.2% vs. 92.1% in whites, P < .001) and those with recurrent HZ were less likely to seek health care for HZ, whereas those with severe pain were more likely (95.4% vs. 87.9% in those without severe pain, P < .01).

Conclusions

HRS provides a new platform for studies of HZ, one which allowed us to uncover issues that warrant particular attention when interpreting results of health care–based studies.

Herpes Zoster and Risk of Cancer in the Elderly U.S. Population

BACKGROUND

Herpes zoster (HZ) arises in older people due to age-related decline in immunity. We assessed whether HZ, as a marker of immune suppression, is associated with increased cancer risk.

METHODS

We conducted a case-control study in U.S. adults with ages ≥ 65 years using the Surveillance, Epidemiology, and End Results (SEER)-Medicare linked database. Cases (n = 1,108,986) were people with first cancers identified in cancer registries (1992-2005). Controls (n = 100,000) were cancer-free individuals frequency matched to cases on age, sex, and year of selection. We identified HZ diagnosis using Medicare claims. Logistic regression models were constructed to determine adjusted associations between cancer and HZ.

RESULTS

HZ prevalence was modestly higher in cases than controls (1.4% vs. 1.2%). We identified significant associations between HZ and oral cavity/pharyngeal [adjusted OR (aOR) = 1.21], colon (aOR = 1.10), lung (aOR = 1.11), and non-melanoma skin (aOR = 1.46) cancers; myeloma (aOR = 1.38); diffuse large B-cell lymphoma (aOR = 1.30); lymphoplasmacytic lymphoma (aOR = 1.99); and chronic lymphocytic leukemia/small lymphocytic lymphoma (aOR = 1.55). Among solid cancers, HZ was mostly associated with regional and/or distant stage tumors. Associations were strongest when HZ was diagnosed 13 to 35 months before cancer diagnosis/selection; they were significant for some cancers in the 36 to 59 months period, and 60+ months for lymphoplasmacytic lymphoma (OR = 1.99).

CONCLUSION

HZ is associated with modestly increased risk of a few cancers, particularly hematologic malignancies. Associations were strongest at short latency intervals for many cancers, and for regional/distant stages among solid cancers, perhaps reflecting reverse causality.

IMPACT

Age-related immune decline does not play a major role in cancer development in older people, but it may be important for some lymphomas.

The bidirectional relationship between pain intensity and sleep disturbance/quality in patients with low back pain

OBJECTIVES

This study investigated the bidirectional relationship between the intensity of low back pain (LBP) and sleep disturbance. Further, the study aimed to determine whether any relationship is dependent on pain duration, symptoms of depression and anxiety, and the method of sleep assessment (subjective vs. objective).

MATERIALS AND METHODS

Eighty patients with LBP completed a sleep diary. A subgroup of 50 patients additionally wore an electronic device (Armband) to measure sleep for 7 consecutive days. Pain intensity was assessed twice daily using a sleep diary. Depression and anxiety symptoms were assessed at baseline using the Depression Anxiety Stress Scale questionnaire. Generalized estimating equations (GEE) with an exchangeable correlation structure were used to examine the relationship between day-time pain intensity and sleep.

RESULTS

The GEE analysis showed that a night of poor sleep quality, difficulty falling sleep (assessed by the sleep diary), waking after sleep onset, and low sleep efficiency (assessed by the sleep diary and Armband) were followed by a day with higher pain intensity. Further, a day with higher pain intensity was associated with a decrease in the subsequent night's sleep quality, an increase in sleep latency (assessed by the sleep diary), waking after sleep onset (assessed by both measures), and low sleep efficiency (assessed by the Armband).

DISCUSSION

The findings demonstrate that there is a bidirectional relationship between sleep and pain intensity in patients with LBP. The relationship is independent of pain duration and baseline symptoms of depression and anxiety and somewhat dependent on the method of sleep measurement (sleep diary or Armband). Future research is needed to determine whether targeting sleep improvement in patients with LBP contributes to pain reduction.

Associations of coping strategies with diary based pain variables among Caucasian and African American patients with osteoarthritis

PURPOSE

The purposes of this study are to examine the associations between pain coping strategies and daily diary-based pain measures and to determine whether these associations differed by race (African American and Caucasian).

METHODS

Primary care patients from the Durham Veterans Affairs and Duke University Medical Centers (N = 153) with hand, hip, or knee osteoarthritis (OA) completed electronic pain diaries on a one-weekend day and one weekday. The maximum, range (maximum minus minimum pain), and area under the curve (AUC) of joint pain ratings were calculated. Pain coping (Coping Strategies Questionnaire (CSQ) coping attempts, catastrophizing, and praying/hoping subscale scores) was assessed prior to diary entries and at the end of each diary day (total, problem-focused, and emotion-focused scores from Stone and Neale's Daily Coping Inventory). Pearson correlations between pain variables and coping measures were examined. Linear mixed models were fit including age, race, weekend/weekday, study enrollment site, education level, pain medication use, self-rated health, Arthritis Impact Measurement Scales affect and function subscales, and interactions of coping measures with race and weekend day/weekday status.

RESULTS

Correlations between coping and pain measures were 0.12-0.45. In adjusted models, maximum pain and pain range were associated with all three diary-based coping measures; maximum pain was associated with CSQ coping attempts; and AUC was associated with CSQ praying/hoping. Interactions were not significant.

CONCLUSIONS

Among participants with OA, pain coping strategies were related to important aspects of the pain experience, particularly pain range and maximum pain. However, race did not modify associations of pain coping strategy use and the pain experience.

Smoking-induced immune deviation contributes to progression of bladder and other cancers

We propose here that cigarette smoke (CS), in addition to its established genotoxic effects, elicits chronic albeit sub-clinical immune suppression, which is a major contributor to cancer progression. This hypothesis, presented here primarily in the context of bladder cancers (BCs), is applicable to other cancers, including those without a confirmed link to smoking.

[Postherpetic neuralgia]

Postherpetic neuralgia is considered to be a neuropathic pain syndrome. Typically, patients experience pain in the dermatomes of skin lesions persisting for more than 3 months after skin restitution. About 10% of patients with herpes zoster develop postherpetic neuralgia. Its prevalence increases with age. Common clinical symptoms include continuous burning pain, sharp pain attacks, and allodynia. Additionally, sensory hyperactivation or loss in the affected skin area is present. Pathophysiology includes mechanisms of peripheral and central sensitization, based on damaged nerve fibers as the main mechanisms for pain generation and its maintenance. Clinical studies did show pain relief in postherpetic neuralgia after administration of antidepressants, antiepileptic drugs, opioids, and topical capsaicin and lidocaine. Nevertheless, about one third of patients do not respond to conventional treatment. Given the fact that postherpetic neuralgia is considered to be a chronic pain disease, a multidisciplinary treatment approach is necessary.

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.

[Postherpetic neuralgia]

Postherpetic neuralgia is considered to be a neuropathic pain syndrome. Typically, patients experience pain in the dermatomes of skin lesions persisting for more than 3 months after skin restitution. About 10% of patients with herpes zoster develop postherpetic neuralgia. Its prevalence increases with age. Common clinical symptoms include continuous burning pain, sharp pain attacks, and allodynia. Additionally, sensory hyperactivation or loss in the affected skin area is present. Pathophysiology includes mechanisms of peripheral and central sensitization, based on damaged nerve fibers as the main mechanisms for pain generation and its maintenance. Clinical studies did show pain relief in postherpetic neuralgia after administration of antidepressants, antiepileptic drugs, opioids, and topical capsaicin and lidocaine. Nevertheless, about one third of patients do not respond to conventional treatment. Given the fact that postherpetic neuralgia is considered to be a chronic pain disease, a multidisciplinary treatment approach is necessary.

Preventing and managing herpes zoster: key actions to foster healthy aging

Population aging is the demographic phenomenon characterizing all countries in the world, and it is challenging the national infrastructures, in particular health systems. However, aging itself is not associated with increased medical spending, but disability and comorbidity that affect older individuals are the actual drivers for health expenditures. Therefore, if people age in better health, medical spending may be significantly reduced. Preventative interventions proved to be effective in reducing/preventing disease and disability and often found to be cost effective, include diet and exercise interventions, medications, routine disease screenings, and immunizations. Vaccination can protect older citizens against life-threatening diseases, such as influenza, pneumococcal infections, tetanus, and against diseases which adversely impact their quality of life, such as herpes zoster (HZ). Including HZ vaccination in its citizens' lifetime immunization calendar can reinforce Europe's commitment toward active, healthy aging. This paper outlines the consensus statement of a group of Italian experts on HZ.

Burden of herpes zoster-associated chronic pain in Italian patients aged 50 years and over (2009-2010): a GP-based prospective cohort study

Background

Post-herpetic neuralgia (PHN) is the most common complication in herpes zoster (HZ) patients.

Methods

We performed a longitudinal, prospective study in 108 general practices throughout Italy to assess how many immunocompetent patients aged ≥50 years with newly diagnosed HZ develop HZ-associated pain, its duration and management over 6-months. HZ-associated pain was assessed by a direct question to the patient and by self-assessment of the worst pain felt in the previous two weeks on a visual analogue scale (VAS), a score ≥3 was taken as pain. PHN was defined as pain reported during the study period persisting for ≥3 months. Quality of life (QoL) was measured using the SF-12 questionnaire.

Results

At enrolment, 370 of the 413 patients (89.6%) reported HZ-associated pain which was still present in 20.6% and 9.2% of patients after three and six months, respectively, despite many patients receiving recommended anti-viral therapy. The overall QoL scores were lower than those in healthy Italians of similar age; scores for patients with HZ-associated pain were lower. The presence of >50 vesicles and VAS score ≥3 at enrolment, and being male were significantly associated with PHN at three months.

Conclusions

These results suggest that HZ and PHN represent an important burden of disease in the elderly. There is a need for interventions that can prevent and reduce the burden of HZ to help improve the quality of life of the elderly. These data may be useful as baseline epidemiology data for the assessment of the impact of the VZV vaccine in Italy, after its implementation.

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-014-0637-6) contains supplementary material, which is available to authorized users.

Prevention of post-herpetic neuralgia using transcutaneous electrical nerve stimulation

BACKGROUND

Post-herpetic neuralgia (PHN) is the most common complication of herpes zoster (HZ) and is difficult to treat. The role of antiviral agents and nonpharmacologic procedures in preventing PHN is not entirely clear. Recent retrospective study showed that transcutaneous electrical nerve stimulation (TENS) may completely prevent PHN. The aim of our study was to identify predictors for PHN and evaluate the treatment with antiviral agents and TENS.

METHODS

We conducted a multicenter prospective, randomized intervention study in patients with a new onset of HZ. Immunocompromised patients were excluded. Patients were randomly assigned to four groups (TENS, Antiviral agents, TENS and Antiviral agents, and Control Group). At the inclusion, the following criteria were recorded: age, gender, duration of pain before the onset of the rash, the number of efflorescence, the intensity of pain, and the analgesic prescribed. During the follow-up, we recorded a spontaneous pain sensation, pain intensity, and presence of allodynia, hyperalgesia, or paraesthesia.

RESULTS

With each additional year of age, the odds for the presence of PHN with unchanged values of other predictors increase (odds ratio (OR) = 1.03 [1.01; 1.05], p = 0.001). The same is true for the initial intensity of the pain (OR = 1.25 [1.09; 1.43], p = 0.002). The odds for acute and subacute herpetic neuralgia are greater than for PHN. The odds for subacute herpetic neuralgia are the lowest in the group treated with TENS (OR = 0.15 [0.05; 0.47], p = 0.001).

CONCLUSIONS

PHN cannot be completely prevented. TENS as a single therapy was found the most successful among the tested treatments in reducing the incidence of subacute herpetic neuralgia.

Determinants of opioid efficiency in cancer pain: a comprehensive multivariate analysis from a tertiary cancer centre

BACKGROUND

Pain is one of the most terrifying symptoms for cancer patients. Although most patients with cancer pain need opioids, complete relief of pain is hard to achieve. This study investigated the factors influencing persistent pain-free survival (PPFS) and opioid efficiency.

MATERIALS AND METHODS

A prospective study was conducted on 100 patients with cancer pain, hospitalized at the medical oncology clinic of Akdeniz University. Patient records were collected including patient demographics, the disease, treatment characteristics, and details of opioid usage. Pain intensity was measured using a patient self-reported visual analogue scale (VAS). The area under the curve (AUC) reflecting the pain load was calculated from daily VAS tables. PPFS, the primary measure of opioid efficacy, was described as the duration for which a patient reported a greater than or equal to two-point decline in their VAS for pain. Predictors of opioid efficacy were analysed using a multivariate analysis.

RESULTS

In the multivariate analysis, PPFS was associated with the AUC for pain (Exp (B)=0.39 (0.23-0.67), P=0.001), the cumulative opioid dosage used during hospitalisation (Exp (B)=1.00(0.99-1.00), P=0.003) and changes in the opioid dosage (Exp (B)=1.01 (1.00-1.01), P=0.016). The change in VAS score over the standard dosage of opioids was strongly associated with current cancer treatment (chemotherapy vs. others) (β=-0.31, T=-2.81, P=0.007) and the VAS for pain at the time of hospitalisation (β=-0.34, T=-3.07, P= 0.003).

CONCLUSIONS

The pain load, opioid dosage, concurrent usage of chemotherapy and initial pain intensity correlate with the benefit received from opioids in cancer patients.

Frequency, pattern, and extent of skin diseases in relation to CD4+ cell count among adults with human immunodeficiency virus infection or acquired immunodeficiency syndrome in Osogbo, southwestern Nigeria

BACKGROUND

Skin diseases characterize all stages of human immunodeficiency virus (HIV) infection and acquired immunodeficiency syndrome (AIDS) and contribute significantly to associated morbidity and mortality.

OBJECTIVES

The aim of this study was to document the prevalences, patterns, and extents (severity) of skin diseases and their relationships with immunologic status in HIV/AIDS patients.

METHODS

A total of 140 HIV/AIDS patients in different stages of HIV infection and 140 controls were recruited. Skin diseases were documented and CD4+ cell counts determined in all subjects. Severity was assessed according to the body surface area affected (using the Wallace rule of nines and the rule of palm) for lesions that tended to be widespread. The number of digits involved was counted for lesions involving the nails. Intensity of pain was graded for specific conditions such as herpes zoster. Chi-squared statistics and Pearson correlations were determined.

RESULTS

Mean±standard deviation age was 35.04±8.83 years in the patient group and 32.21±8.30 years in the control group. The prevalences and patterns of skin diseases in HIV/AIDS patients were similar to those reported in previous studies. Most commonly found dermatoses were oral candidiasis (n=28, 20.0%), pruritic papular eruption (n=27, 19.3%), xeroderma (n=23, 16.4%), dermatophytosis (n=22, 15.7%), and fluffy hair (n=19, 13.6%). The presence of specific skin lesions represented a better correlate with immunosuppression than cutaneous extents. However, the extents of viral warts and multiple blue–black nails correlated significantly with CD4+ cell count. The presence of a lighter hair color phenotype signifies a lower CD4+ cell count than a softer hair phenotype.

CONCLUSIONS

The presence of specific skin lesions correlates more strongly with a low CD4+ cell count than does the extent of their distribution, except in cases of viral warts. The presence of and higher numbers of nails affected with blue–black nail hyperpigmentation suggest severe immunosuppression.

One-year follow-up of patients with long-lasting post-herpetic neuralgia

BACKGROUND

Recent information on epidemiology and management of post-herpetic neuralgia (PHN), a painful complication of zoster, is scarce.

METHODS

This study was conducted at the Pain Clinic of the Policlinico Tor Vergata, Rome, Italy, on eighty-five immunocompetent patients with a clinical diagnosis of PHN. At enrollment (time 0, T0), the patients were interviewed by physicians to obtain demographic data and information about their zoster clinical history and underwent a blood test for VZV-DNA research. DN4 and SF-12 questionnaires were used to assess the neuropathic nature of pain and the overall health status, respectively. A one-year follow-up was planned for enrolled cases, who were visited at regular intervals of at least 3 months.

RESULTS

At T0 all the patients were at least 6 months from the episode of acute zoster and still presented with intense pain (mean VAS =6.7; mean DN4 = 5.7). Using antivirals within 72 hours from the rash onset was associated to a significant reduction of pain at T0 (p = 0.006 vs untreated patients). Only 2.6% of patients treated with antivirals during acute zoster but 18.6% of the untreated ones presented with neuropathic pain at T12 (p =0.007), even though the two groups were similar at T0. VZV-DNA was found in 5 out of the 50 available blood samples. At the last follow-up visit, PCS and MCS scores of the PHN patients were found to be recovered over those of the historical age-matched healthy controls. Undesirable side effects of analgesic therapies were observed in 15.3 to 28.8% of the patients.

CONCLUSIONS

Patients who six months after acute zoster still have significant neuropathic pain, have a high probability of suffering from chronic pain in the subsequent months/years. The initial antiviral treatment has a significant impact on the pain. Current strategies of analgesic therapy are effective to achieve relief of pain in PHN patients, but they are burdened with heavy and undesirable side effects.

Herpes zoster and postherpetic neuralgia in Catalonia (Spain)

The objective of the study was to analyze the descriptive epidemiology and costs of herpes zoster (HZ) and postherpetic neuralgia (PHN) in people aged ≥50 years in Catalonia (Spain). The incidence of HZ in Catalonia was estimated by extrapolating the incidence data from Navarre (Spain) to the population of Catalonia. The incidence of PHN was estimated according to the proportion of cases of HZ in the case series of the Hospital del Sagrado Corazón de Barcelona that evolved to PHN. Drug costs were obtained directly from the prescriptions included in the medical record (according to official prices published by the General Council of the College of Pharmacists). The cost of care was obtained by applying the tariffs of the Catalan Health Institute to the number of outpatient visits and the number and duration of hospital admissions. The estimated annual incidence of HZ was 31 763, of which 21 532 (67.79%) were in patients aged ≥50 years. The respective figures for PHN were 3194 and 3085 (96.59) per annum, respectively. The mean cost per patient was markedly higher in cases of PHN (916.66 euros per patient) than in cases of HZ alone (301.52 euros per patient). The cost increased with age in both groups of patients. The estimated total annual cost of HZ and its complications in Catalonia was € 9.31 million, of which 6.54 corresponded to HZ and 2.77 to PHN. This is the first Spanish study of the disease burden of HZ in which epidemiological data and costs were collected directly from medical records. The estimated incidence of HZ is probably similar to the real incidence. In contrast, the incidence of PHN may be an underestimate, as around 25% of patients in Catalonia attend private clinics financed by insurance companies. It is also probable that the costs may be an underestimate as the costs derived from the prodromal phase were not included. In Catalonia, HZ and PHN cause an important disease burden (21 532 cases of HZ and 3085 de PHN with an annual cost of € 9.31 million) in people aged ≥50 years, in whom vaccination is indicated.

Peptic ulcer as a risk factor for postherpetic neuralgia in adult patients with herpes zoster

Postherpetic neuralgia is the most common complication of herpes zoster. Identifying predictors for postherpetic neuralgia may help physicians screen herpes zoster patients at risk of postherpetic neuralgia and undertake preventive strategies. Peptic ulcer has been linked to immunological dysfunctions and malnutrition, both of which are predictors of postherpetic neuralgia. The aim of this retrospective case-control study was to determine whether adult herpes zoster patients with peptic ulcer were at greater risk of postherpetic neuralgia. Adult zoster patients without postherpetic neuralgia and postherpetic neuralgia patients were automatically selected from a medical center's electronic database using herpes zoster/postherpetic neuralgia ICD-9 codes supported with inclusion and exclusion criteria. Consequently, medical record review was performed to validate the diagnostic codes and all pertaining data including peptic ulcer, Helicobacter pylori (H. pylori) infection and ulcerogenic medications. Because no standard pain intensity measurement exists, opioid usage was used as a proxy measurement for moderate to severe pain. In total, 410 zoster patients without postherpetic neuralgia and 115 postherpetic neuralgia patients were included. Multivariate logistic regressions identified 60 years of age and older, peptic ulcer and greater acute herpetic pain as independent predictors for postherpetic neuralgia. Among etiologies of peptic ulcer, H. pylori infection and usage of non-selective nonsteroidal anti-inflammatory drugs were significantly associated with the increased risk of postherpetic neuralgia; conversely, other etiologies were not significantly associated with the postherpetic neuralgia risk. In conclusion, 60 years of age and older, peptic ulcer and greater acute herpetic pain are independent predictors for postherpetic neuralgia in adult herpes zoster patients.

Poor sleep quality is strongly associated with subsequent pain intensity in patients with acute low back pain

OBJECTIVE

Recent research suggests that sleep quality and pain intensity are intimately linked. Although sleep problems are common in patients with low back pain, the effect of sleep quality on the levels of pain intensity is currently unknown. The aim of this study was to investigate the effect of sleep quality on subsequent pain intensity in patients with recent-onset low back pain.

METHODS

Data on 1,246 patients with acute low back pain were included in the analysis. Sleep quality was assessed using the sleep quality item of the Pittsburgh Sleep Quality Index, scored on a 0-3-point scale, where 0 = very good sleep quality and 3 = very bad sleep quality. Pain intensity was assessed on a numerical rating scale (range 0-10). A generalized estimating equation (GEE) analysis modeled with an exchangeable correlation structure was used to examine the relationship between sleep quality and pain intensity. The model further controlled for symptoms of depression and prognostic factors for low back pain.

RESULTS

The GEE analysis demonstrated a large effect of poor sleep on subsequent pain intensity, such that for every 1-point decrease in sleep quality (based on a 0-3-point scale), pain intensity (based on a 0-10-point scale) increased by 2.08 points (95% confidence interval 1.99-2.16). This effect was independent of depression and common prognostic factors for low back pain.

CONCLUSION

Sleep quality is strongly related to subsequent pain intensity in patients with acute low back pain. Future research is needed to determine whether targeting sleep improvement contributes to pain reduction.

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.

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.

Incidence and time trends of herpes zoster in rheumatoid arthritis: a population-based cohort study

OBJECTIVE

To determine the incidence, time trends, risk factors, and severity of herpes zoster in a population-based cohort of patients with newly diagnosed rheumatoid arthritis (RA) compared to a group of individuals without RA from the same population.

METHODS

All residents of Olmsted County, Minnesota fulfilling for the first time the 1987 American College of Rheumatology criteria for RA between January 1, 1980 and December 31, 2007 and a cohort of similar residents without RA were assembled and followed by retrospective chart review until death, migration, or December 31, 2008.

RESULTS

There was no difference in the presence of herpes zoster prior to the RA incidence/index date between the cohorts (P = 0.85). During followup, 84 patients with RA (rate 12.1 cases per 1,000 person-years) and 44 subjects without RA (rate 5.4 cases per 1,000 person-years) developed herpes zoster. Patients with RA were more likely to develop herpes zoster than those without RA (hazard ratio [HR] 2.4 [95% confidence interval (95% CI) 1.7-3.5]). Herpes zoster occurred more frequently in patients diagnosed with RA more recently (HR 1.06 per year [95% CI 1.02-1.10]). Erosive disease, previous joint surgery, and use of hydroxychloroquine and corticosteroids were significantly associated with the development of herpes zoster in RA. There was no apparent association of herpes zoster with the use of methotrexate or biologic agents. Complications of herpes zoster occurred at a similar rate in both cohorts.

CONCLUSION

The incidence of herpes zoster is increased in RA and has risen in recent years. There also has been an increasing incidence of herpes zoster in more recent years in the general population. RA disease severity is associated with the development of herpes zoster.

Natural history of herpes zoster: late follow-up of 3.9 years (n=43) and 7.7 years (n=10)

Postherpetic neuralgia (PHN) is a common complication after herpes zoster (HZ). Subjects who completed a longitudinal observational 6-month study (4 visits) of the natural history of HZ were recontacted for 2 additional follow-up visits that included pain and sensory symptom assessment, quantitative sensory testing, capsaicin response test, and 3-mm punch skin biopsies in HZ-affected, mirror-image, and control skin sites. Forty-three subjects (14 with PHN at 6 months) of the original 94 subjects in the cohort were comprehensively assessed at a median 3.9 years after HZ onset (visit 5), and 10 subjects underwent a final assessment at a median 7.7 years after HZ onset (visit 6). At 3.9 years, none of the 29 subjects who had been pain free at 6 months had a recurrence of pain. Only 2 of the 14 subjects with PHN at 6 months still had pain at 3.9 years. One subject with PHN at 6 months was free of symptoms at 3.9 years but had very mild pain at 7.7 years. Sensory function continued on a path toward normalization, but was still abnormal in many subjects, especially those who met criteria for PHN at 6 months. Even at 7.7 years, reinnervation of HZ-affected skin was not apparent.

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.

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.

Predictors of severe pain in a cohort of 5271 individuals with self-reported neuropathic pain

The influence of pain descriptors and mechanical hypersensitivity on pain severity in neuropathic pain has not been well researched and is poorly understood. The aim of this study was to determine the relationship between pain severity and other factors describing chronic neuropathic pain in a large cohort of patients with self-reported neuropathic pain potentially recruited as subjects for a Phase IIa study. A questionnaire specific to the study parameters covering demographics and pain characteristics was sent to potential participants. Overall, 9185 questionnaires were returned from potential subjects who self-reported neuropathic pain. Adjusted odds ratios with 95% confidence intervals were used as a measure of association. These were estimated by unconditional logistic regression. Pain descriptors in the questionnaire were: burning, shooting, shocking, and aching. The presence of self-reported allodynia and hyperalgesia was strongly indicative of both moderate and severe pain, with a significant interaction of both factors in moderate and severe pain. Having 3 or 4 pain descriptors was also strongly indicative of both moderate and severe pain. Female gender, age, and history of serious mental disorders were found to be weaker indicators of both moderate and severe pain. Given the large and varied population with many neuropathic pain diagnoses in the study, the findings are not likely to be merely chance, but are likely to reflect important relationships between pain severity and other factors in those who suffer from chronic neuropathic pain.