Healthcare Utilization in People with Postherpetic Neuralgia and Painful Diabetic Peripheral Neuropathy

A pharmacoeconomic evaluation of the pharmacotherapeutic options for painful diabetic neuropathy

INTRODUCTION

Painful diabetic neuropathy (PDN) is a high incidence and severe complication of diabetes mellitus, significantly compromising patients' quality of life and causing tremendous economic burden. Considering drug costs becomes part of treatment decisions, with the growing choice of monotherapy or combination treatment strategies for PDN treatment.

AREAS COVERED

This systematic review aims to identify the cost-effectiveness of pharmacotherapies in PDN, summarize key findings, and assess the quality of studies to inform healthcare resource allocation decisions and future research. Economic evaluations were identified by searching PubMed, Web of Science, Scopus and health technology assessment (HTA) databases, as well as screening reference lists of previously identified studies. Relevant data was extracted, and the CHEERS checklist was used to assess the quality of the studies.

EXPERT OPINION

Collectively, the findings indicate that more pharmacoeconomics research is urgently needed to directly compare high-quality research for PDN combination medication/sequential treatment, and which is performed from a societal perspective. Simultaneously, to strengthen the reliability of the analysis, metrics such as adherence, incidence of adverse drug reactions, and pain levels utility value should be examined to verify the robustness of the basic results.

10.6-μm infrared laser as adjuvant therapy for diabetic peripheral neuropathy: study protocol for a double-blind, randomized controlled trial

Background

Diabetic peripheral neuropathy (DPN) is the most common chronic neurological complication. It is the main cause of disability in diabetes mellitus (DM) patients and seriously affects the quality of life of patients. Pharmacological treatments always associate with limited efficacy and adverse effects. Moxibustion has been recommended to treat DPN as an adjuvant therapy to conventional medical treatment to accelerate alleviation of the symptoms of DPN. 10.6-μm laser moxibustion (LM), whose wavelength is close to the peak of infrared radiation spectrum of the traditional moxibustion as well as human acupoints, produces the thermal effect similar with moxibustion but with no smoke or smell. The purpose of this sham controlled clinical trial is to determine the effect and safety of 10.6-μm LM as adjuvant therapy in patients with DPN.

Methods

This is a protocol for a randomized, double-blind, sham-controlled trial. One hundred fourteen patients meeting the inclusion and exclusion criteria will be recruited and randomly assigned to the LM group or the sham LM group with a 1:1 allocation ratio. Patients in both groups will receive a basic integrated treatment of Chinese and Western medicine and a total of 12 sessions of true or sham LM treatments over 4 weeks with 3 sessions a week. The primary outcome is nerve conduction velocity (NCV), and the secondary outcomes include Michigan Neuropathy Screening Instrument (MNSI) scores, Diabetes-Specific Quality of Life (DSQL) scores, blood rheology parameters, and assessments of safety and blinding. Outcome measures will be collected at baseline, 2 weeks after treatment, the end of LM treatments (4 weeks), and 4, 8 weeks after the end of LM treatment (8, 12weeks).

Discussion

This study will be conducted to compare the efficacy of LM versus sham LM combined with medical treatment. 10.6-μm LM may alleviate symptoms, improve quality of life, and reduce the dosage of drugs as well as avoid causing serious side effects.

Trial registration

Chinese Clinical Trial Registry ChiCTR2000029329. Registered on 25 January 2020.

Corneal Confocal Microscopy: A Biomarker for Diabetic Peripheral Neuropathy

PURPOSE

Diagnosing early diabetic peripheral neuropathy remains a challenge due to deficiencies in currently advocated end points. The cornea is densely innervated with small sensory fibers, which are structurally and functionally comparable to intraepidermal nerve fibers. Corneal confocal microscopy is a method for rapid, noninvasive scanning of the living cornea with high resolution and magnification.

METHODS

This narrative review presents the framework for the development of biomarkers and the literature on the use and adoption of corneal confocal microscopy as an objective, diagnostic biomarker in experimental and clinical studies of diabetic peripheral neuropathy. A search was performed on PubMed and Google Scholar based on the terms "corneal confocal microscopy," "diabetic neuropathy," "corneal sensitivity," and "clinical trials."

FINDINGS

A substantial body of evidence underpins the thesis that corneal nerve loss predicts incident neuropathy and progresses with the severity of diabetic peripheral neuropathy. Corneal confocal microscopy also identifies early corneal nerve regeneration, strongly arguing for its inclusion as a surrogate end point in clinical trials of disease-modifying therapies.

IMPLICATIONS

There are sufficient diagnostic and prospective validation studies to fulfill the US Food and Drug Administration criteria for a biomarker to support the inclusion of corneal confocal microscopy as a primary end point in clinical trials of disease-modifying therapies in diabetic neuropathy.

Management of Neuropathic Pain in Polyneuropathy

PURPOSE OF REVIEW

Many polyneuropathies cause significant neuropathic pain, resulting in substantial morbidity and reduced quality of life. Appropriate management is crucial for maintaining quality of life for patients with painful polyneuropathies. The US Food and Drug Administration (FDA) has only approved one new drug for painful diabetic neuropathy in the past decade, a topical capsaicin patch that was initially approved for the treatment of postherpetic neuralgia in 2009. Gabapentinoids and serotonin norepinephrine reuptake inhibitors (SNRIs) continue to have an advantage in safety profiles and efficacy. Other antiepileptic medications remain second-line agents because of fewer studies documenting efficacy.

RECENT FINDINGS

This article reviews recent literature on complementary and pharmacologic therapies for the management of painful polyneuropathies. Exercise has emerged as an important therapeutic tool and may also improve the underlying polyneuropathy in the setting of obesity, metabolic syndrome, and diabetes.

SUMMARY

The approach to management of painful polyneuropathies is multifactorial, using both pharmacologic and nonpharmacologic measures to improve pain severity and patient quality of life.

Treatment Patterns and Medication Use in Patients with Postherpetic Neuralgia

BACKGROUND

Postherpetic neuralgia (PHN) is a chronic, painful condition characterized by persistent pain following resolution of a herpes zoster (HZ) infection. Epidemiologic data demonstrate that the risks for HZ infections and the development of PHN increase with age.

OBJECTIVE

To characterize prescribing patterns, health care utilization, and treatment costs for adults with PHN based on real-world data.

METHODS

This study analyzed medical and pharmacy claims from 2010 to 2014 in the MarketScan Commercial and Medicare Supplemental databases. PHN patients were identified based on criteria from a published algorithm. PHN treatment patterns were analyzed by age and reported descriptively for patients aged < 65 or ≥ 65 years. Excess incremental health care costs were calculated for PHN patients by comparing expenditures for a cohort of PHN patients to expenditures of a propensity score-matched control group of patients with HZ alone.

RESULTS

Approximately 0.4% of patients aged < 65 years were diagnosed with HZ versus 1.3% of patients aged ≥ 65 years; approximately 15.3% of HZ patients aged < 65 years and 26.4% of patients aged ≥ 65 years were diagnosed with PHN. Overall, opioids remained the most frequently prescribed initial treatment. Approximately 21.6% of PHN patients received an opioid as an initial treatment for PHN, 15.1% received gabapentin; 8.9% received a prescription nonsteroidal anti-inflammatory drug (NSAID); 8.3% received a lidocaine patch; 3.3% received pregabalin; 2.5% received a tricyclic antidepressants (TCAs); 0.8% received other topical lidocaine; and < 1% received capsaicin. Observed first-line use of the lidocaine patch and gabapentin was higher in patients aged ≥ 65 years relative to patients aged < 65 years. When separated by age group, only 24.6% of patients aged < 65 years and 38.5% of patients aged ≥ 65 years were prescribed a recommended first-line treatment for initial PHN therapy (gabapentin, lidocaine patch, pregabalin, and TCAs). Comparisons of treatment costs of PHN patients to matched HZ patients without PHN indicated that PHN patients initiated on opioids had the highest mean additional health care expenditure compared with PHN patients initiated on other medications. On average, PHN patients initiated on opioids had $7,601 additional health care expenditure compared with HZ patients with no PHN; additional expenditures were $6,428 for pregabalin, $4,213 for lidocaine patches, $3,478 for gabapentin, $3,304 for NSAIDs, and $2,797 for TCAs, respectively.

CONCLUSIONS

Management of PHN is associated with substantial utilization of opioid-based therapies across all ages. Medications supported by evidence either as first-line therapies or as part of a multimodal regimen for the management of PHN are underused relative to opioid-based PHN therapies. Improving adherence to evidence-based PHN treatment regimens offers the potential to reduce opioid prescribing first line and reduce overall treatment costs. Given the emphasis to reduce opioid prescribing to minimize the risk of dependence, abuse, and diversion, multimodal analgesic treatments that can avoid or reduce opioid use should be considered.

DISCLOSURES

Research funding was provided by SCILEX Pharmaceuticals. The sponsor reviewed and approved the research plan and provided support for manuscript preparation through Patel's role as a coauthor of this manuscript. The sponsor's product (lidocaine patch) was not used in this study. Patel is a paid employee of SCILEX Pharmaceuticals. Goss is an employee and minority owner of Boston Healthcare Associates, which received a research grant from SCILEX Pharmaceuticals to conduct this study. Gudin reports advisory board fees from AcelRx Pharmaceuticals and BioDelivery Sciences International and consulting fees from Averitas, Daiichi, Hisumitsu, Nektar, Purdue, Quest Diagnostics, SCILEX Pharmaceuticals, and US WorldMeds, unrelated to this study. Fudin reports advisory board fees from AcelRx Pharmaceuticals, Human Half-Cell, Quest Diagnostics, GlaxoSmithKline, SCILEX Pharmaceuticals, BioDelivery Sciences, Daiichi Sankyo, and Salix Pharmaceuticals; speaker fees from Daiichi Sankyo, Salix Pharmaceuticals, Abbott Laboratories, Acutis Diagnostics, and AstraZeneca; and consulting fees from Firstox Laboratories, unrelated to this study. The other authors have nothing to disclose. Parts of this research were presented at the AMCP Managed Care & Specialty Pharmacy Annual Meeting; April 22, 2016; San Francisco, CA, and at the 35th Annual Scientific Meeting of the American Pain Society; May 11-14, 2016; Austin, TX.

Using Random Forest Models to Identify Correlates of a Diabetic Peripheral Neuropathy Diagnosis from Electronic Health Record Data

Objective

To identify variables correlated with a diagnosis of diabetic peripheral neuropathy (DPN) using random forest modeling applied to electronic health records.

Design

Retrospective analysis.

Setting

Humedica de-identified electronic health records database.

Subjects

Subjects ≥ 18 years old with type 2 diabetes from January 1, 2008-September 30, 2013 having continuous data for 1 year pre- and postindex with DPN (n = 35,050) and without DPN (n = 288,328) were identified.

Methods

Demographic, clinical, and health care resource utilization variables (e.g., inpatient and outpatient encounters, medications, and procedures) were input into a random forest model to identify the most important correlates of a DPN diagnosis. Random forest modeling is a computationally extensive, robust data mining technique that accommodates large sets of variables to identify associated factors using an ensemble of classifications trees. Accuracy of the model was evaluated using receiver operating characteristic curves (ROC).

Results

The final random forest model consisted of the following variables (importance) associated with a DPN diagnosis: Charlson Comorbidity Index score (100%), age (37.1%), number of pre-index procedures and services (29.7%), number of pre-index outpatient prescriptions (24.2%), number of pre-index outpatient visits (18.3%), number of pre-index laboratory visits (16.9%), number of pre-index outpatient office visits (12.1%), number of inpatient prescriptions (5.9%), and number of pain-related medication prescriptions (4.4%). ROC analysis confirmed model performance, with an area under the curve of 0.824 and accuracy of 89.6% (95% confidence interval 89.4%, 89.8%).

Conclusions

Random forest modeling can determine likelihood of a DPN diagnosis. Further validation of the random forest model may help facilitate earlier diagnosis and enhance management strategies.

Effect of Intravenous Alfentanil on Nonpainful Thermally Induced Hyperalgesia in Healthy Volunteers

Experimental interventions that activate specific components of clinical pain are necessary for characterization of underlying mechanisms and pharmacology. Cutaneous hyperalgesia has been described that uses nonpainful heat to induce secondary hyperalgesia. This study evaluated the effect of intravenous alfentanil on experimental cutaneous hyperalgesia created using this method. Eighteen subjects participated in a randomized, double-blinded, placebo-controlled crossover study consisting of 2 sessions, 1 with alfentanil and 1 with placebo. Using a computer-controlled infusion pump, alfentanil or matching placebo was maintained at a constant plasma level of 75 ng/mL for 1 hour followed by the application of a 40°C heat stimulus to the right thenar eminence for 15 minutes. The temperature was raised by 1°C every 15 minutes until the subject reported pain or 45°C was reached. After the end point was reached, the temperature was maintained, and repeat testing was performed. The nonpainful heat created an area of secondary cutaneous hyperalgesia and significant decrease in mechanical pain threshold on heat-treated right vs untreated left during placebo administration. Alfentanil prevented the hypersensitivity when compared to placebo (P < .05) but failed to reduce the area of secondary hyperalgesia created by nonpainful heat when compared to placebo (P = .06). Neither alfentanil nor the heat lamp treatment showed any significant effect on other neurosensory measures. This study demonstrated a reliable production of cutaneous hyperalgesia using a nonpainful stimulus that is affected by the systemic delivery of alfentanil. This model for human cutaneous experimental pain may be a useful method for scientific characterization of analgesics.

Pain severity, interference, and prescription analgesic use among depressed, low-income homebound older adults

OBJECTIVES

Disabled, homebound individuals tend to suffer both chronic pain and depression; however, low-income, homebound older adults have been underexposed in pain and depression research. We examined the extent of pain frequency, intensity, and interference; the relationship between pain and depressive symptoms; and prescription analgesic use and its association with use of antidepressant and anxiolytic medications among these older adults.

METHOD

The data came from the baseline assessment of 215 homebound individuals aged 50+ who were referred to a clinical trial of depression treatment. Bivariate and multivariate analyses were used to examine the research questions.

RESULTS

Almost 87% (n = 186) of the participants reported having had chronic pain in the preceding three months. Of the pain reporters, the mean frequency, intensity, and interference of pain were 8.65 ± 2.05, 7.71 ± 2.10, and 7.80 ± 2.82, respectively, on a 1-10 scale, and 61% were taking a prescription analgesic. Analgesic users and nonusers did not differ in depressive symptoms and in pain frequency and intensity, but analgesic users reported higher pain interference than nonusers (8.22 ± 2.46 vs. 7.14 ± 3.22; t = 2.44, df = 184, p = .016). Pain frequency and interference were significantly associated with depressive symptoms, and pain interference was significantly associated with analgesic use in multivariate analysis. Anxiolytic medication use was also correlated with analgesic use.

CONCLUSION

The findings underscore the significant pain-related problems in these vulnerable individuals and the need for recognizing and treating both pain and depression more effectively using both pharmacologic and nonpharmacologic interventions.

Cost Burden of Chronic Pain Patients in a Large Integrated Delivery System in the United States

OBJECTIVES

To estimate all-cause healthcare resource utilization and costs among chronic pain patients within an integrated healthcare delivery system in the United States.

METHODS

Electronic medical records and health claims data from the Henry Ford Health System were used to determine healthcare resource utilization and costs for patients with 24 chronic pain conditions. Patients were identified by ≥ 2 ICD-9-CM codes ≥ 30 days apart from January to December, 2010; the first ICD-9 code was the index event. Continuous coverage for 12 months pre- and postindex was required. All-cause direct medical costs were determined from billing data.

RESULTS

A total of 12,165 patients were identified for the analysis. After pharmacy, the most used resource was outpatient visits, with a mean of 18.8 (SD 13.2) visits per patient for the postindex period; specialty visits accounted for 59.0% of outpatient visits. Imaging was utilized with a mean of 5.2 (SD 5.5) discrete tests per patient, and opioids were the most commonly prescribed medication (38.7%). Annual direct total costs for all conditions were $386 million ($31,692 per patient; a 40% increase from the pre-index). Pharmacy costs comprised 14.3% of total costs, and outpatient visits were the primary cost driver.

CONCLUSIONS

Chronic pain conditions impose a substantial burden on the healthcare system, with musculoskeletal conditions associated with the highest overall costs. Costs appeared to be primarily related to use of outpatient services. This type of research supports integrated delivery systems as a source for assessing opportunities to improve patient outcomes and lower the costs for chronic pain patients.

A retrospective, matched cohort study of potential drug-drug interaction prevalence and opioid utilization in a diabetic peripheral neuropathy population initiated on pregabalin or duloxetine

Background

Anticipating and controlling drug-drug interactions (DDIs) in older patients with painful diabetic peripheral neuropaty (pDPN) presents a significant challenge to providers. The purpose of this study was to examine the impact of newly initiated pregabalin or duloxetine treatment on Medicare Advantage Prescription Drug (MAPD) plan pDPN patients’ encounters with potential drug-drug interactions, the healthcare cost and utilization consequences of those interactions, and opioid utilization.

Methods

Study subjects required a pregabalin or duloxetine pharmacy claim between 07/01/2008-06/30/2012 (index event), ≥1 inpatient or ≥2 outpatient medical claims with pDPN diagnosis between 01/01/2008-12/31/2012, and ≥12 months pre- and ≥6 post-index enrollment. Propensity score matching was used to balance the pregabalin and duloxetine cohorts on pre-index demographics and comorbidities. Potential DDIs were defined by Micromedex 2.0 and identified by prescription claims. Six-month post-index healthcare utilization (HCU) and costs were calculated using pharmacy and medical claims.

Results

No significant differences in pre-index demographics or comorbidities were found between pregabalin subjects (n = 446) and duloxetine subjects (n = 446). Potential DDI prevalence was significantly greater (p < 0.0001) among duoxetine subjects (56.7%) than among pregabalin subjects (2.9%). There were no significant differences in HCU or costs between pregablin subjects with and without a potential DDI. By contrast, duloxetine subjects with a potential DDI had higher mean all-cause costs ($13,908 vs. $9,830; p = 0.001), more subjects with ≥1 inpatient visits (35.6% vs 25.4%; p = 0.02), and more subjects with ≥1 emergency room visits (32.8% vs. 20.7%; p = 0.005) in comparison to duloxetine subjects without a potential DDI. There was a trend toward a difference between pregabalin and duloxetine subjects in their respective pre-versus-post differences in milligrams (mg) of morphine equivalents/30 days used (60.2 mg and 176.9 mg, respectively; p = 0.058).

Conclusion

The significantly higher prevalence of potential DDIs and potential cost impact found in pDPN duloxetine users, relative to pregabalin users, underscore the importance of considering DDIs when selecting a treatment.

Healthcare utilization and costs in diabetes relative to the clinical spectrum of painful diabetic peripheral neuropathy

AIMS

Diabetic peripheral neuropathy (DPN) accompanied by painful symptoms is known as painful DPN (pDPN). This study characterized healthcare resource utilization and costs in patients with DPN, pDPN, and severe pDPN relative to diabetes only.

METHODS

Four adult cohorts were identified from the Humedica database: type 2 diabetes without DPN (n=288,328); DPN (n=35,050); pDPN (DPN subjects with a pain score ≥1 on a 0-10 numeric rating scale; n=3449); and severe pDPN (pain scores 7-10; n=1824). Resource utilization and costs for 12-months post-diagnosis were compared for diabetes relative to the other cohorts.

RESULTS

Demographic characteristics were different across cohorts. Relative to diabetes alone, DPN, pDPN, and severe pDPN were characterized by significantly higher proportions of patients with resource utilization for all resource categories (all P<0.0001); the highest resource use generally observed for severe pDPN. Total annual direct medical costs were $6632 for diabetes only, with costs for DPN ($12,492), pDPN ($27,931), and severe pDPN ($30,755) significantly higher (all P<0.0001); outpatient costs were consistently the primary driver of total costs.

CONCLUSIONS

Patients with DPN, pDPN, and severe pDPN had significantly greater healthcare resource utilization and costs than patients with diabetes only, with the highest burden associated with severe pDPN.

Pain severity and the economic burden of neuropathic pain in the United States: BEAT Neuropathic Pain Observational Study

Background

As with many chronic conditions, patients with neuropathic pain (NeP) are high consumers of health care resources. However, limited literature exists on the economic burden of NeP, including its impact on productivity. The aim of this study was to characterize health care resource utilization, productivity, and costs associated with NeP by pain severity level in US adults.

Methods

Subjects (n=624) with painful diabetic peripheral neuropathy, human immunodeficiency virus-related peripheral NeP, post-trauma/post-surgical NeP, spinal cord injury with NeP, chronic low back pain with NeP, and small fiber neuropathy were recruited during routine office visits to US community-based general practitioners and specialists. Clinicians captured clinical characteristics, NeP-related medications, and health care resource utilization based on 6-month retrospective medical chart review. Subjects completed questionnaires on demographics, pain/symptoms, costs, and productivity. Brief Pain Inventory pain severity scores were used to classify subjects by mild, moderate, or severe pain. Annualized NeP-related costs (adjusted for covariates) were estimated, and differences across pain severity groups were evaluated.

Results

In total, 624 subjects were recruited (mean age 55.5±13.7 years; 55.4% male), and 504/624 (80.8%) reported moderate or severe pain. Statistically significant differences were observed across pain severity levels for number of comorbidities, prescription medications, physician office visits, and lost productivity (all P≤0.0001). At all pain severity levels, indirect costs were the primary cost driver. After adjusting for demographic and clinical variables, total mean (95% confidence interval [CI]) annualized direct medical costs to payers, direct costs to subjects, and indirect costs per subject were US$6,016 (95% CI 5,316–6,716), US$2,219 (95% CI 1,919–2,519), and US$19,000 (95% CI 17,197–20,802), respectively, with significant differences across pain severity levels.

Conclusion

Subjects with NeP, mainly those showing moderate or severe pain, had significant associations between pain severity and NeP-related health care resource utilization, productivity, and costs. The economic burden, particularly indirect costs, was highest among those with severe pain and higher than previously reported in studies of specific NeP conditions.

Painful diabetic peripheral neuropathy: results of a survey characterizing the perspectives and misperceptions of patients and healthcare practitioners

Background

Little information exists on the understanding and management of painful diabetic peripheral neuropathy (pDPN) between patients and healthcare practitioners (HCPs).

Objective

The objective of this study was to characterize the patient perspective of pDPN and identify gaps in patient and HCP perceptions of pDPN.

Methods

An online survey of patients with type 1 or 2 diabetes mellitus who reported experiencing any symptoms consistent with diabetic peripheral neuropathy (DPN) and HCPs who treat diabetes was conducted in 2012 in the USA. Patients were recruited via the Survey Sampling national consumer research panel, and HCPs were recruited from Epocrates’ national research panel. Survey questions focused on the impact, understanding, and management of pDPN, and interactions between patients and their HCPs. Respondents who reported pain were re-contacted to obtain further information on pain severity using a numerical rating scale (0 = no pain, 10 = most pain).

Results

Respondents included 1,004 patients (53 % female, average age 55 years) and 500 HCPs (250 generalists, 150 specialists, and 100 nurses/physician assistants). While 83 % of patients reported pDPN symptoms, only 41 % of these patients had been diagnosed with DPN. Eighty-five percent of those with pDPN reported that it impacts daily activities. In contrast, HCPs estimated that of their patients who experienced any type of DPN symptom, 41 % experienced pain and 38 % had daily activity limitations because of their symptoms. Most HCPs (64 %) never had their patients complete a DPN assessment questionnaire, and only 41 % perform specific diagnostic tests on all patients who report DPN symptoms. Patients and HCPs both showed substantial clinical misperceptions regarding the cause and management of pDPN; 53 % of HCPs believed that adequate blood glucose control could reverse DPN, and 43 % of pDPN patients were not sure if DPN was reversible. There was also substantial discordance between patients and HCPs regarding discussions of DPN; only 49 % of pDPN patients reported that they speak about symptoms at “every” or “most” appointments with their HCP but 73 % of HCPs reported discussing DPN symptoms at “every” or “most” visits.

Conclusions

Not only do misperceptions exist on the cause and management of pDPN among patients and HCPs, but there are additional disparities between the patient and HCP perspectives. These results suggests a need for (1) educational initiatives on pDPN that target patients and HCPs, and (2) initiating improved dialogue between patients and their HCPs for discussing appropriate management of pDPN that is distinct from treatment of the underlying diabetes.

Electronic supplementary material

The online version of this article (doi:10.1007/s40271-013-0038-8) contains supplementary material, which is available to authorized users.

Assessment and management of neuropathic pain in primary care

SUMMARY Most patients with neuropathic pain present and are managed in primary care. It is generally a long-term condition associated with poor physical, psychological and social health. Assessment and pharmacological treatment algorithms, specifically designed for primary care, are now available. The focus should be on taking a good medical history and clinical examination, and with the knowledge of the patient's current and past medical history, the general practitioner can diagnose possible neuropathic pain and initiate treatment while awaiting specialist assessment (if required). Specific nonpharmaceutical interventions, though popular with patients, have thus far demonstrated limited effectiveness. General practitioners, with their long-term relationship with patients, have a central role in improving the diagnosis and management of neuropathic pain.

Relationship between persistent pain and 5-year mortality: a population-based prospective cohort study

OBJECTIVES

To assess the association between self-reported noncancer pain and 5-year mortality.

DESIGN

Cohort.

SETTING

Community-dwelling older adults.

PARTICIPANTS

Canadian Study of Health and Aging 1996 wave.

MEASUREMENTS

Registrar of Vital Statistics-established 5-year mortality. Noncancer pain was assessed using the 5-point verbal descriptor scale, dichotomized into no or very mild versus moderate, severe, or very severe pain. Frailty was the accumulation of health deficits. Cognitive status (Modified Mini-Mental State Examination) and depressed mood (five-item mental health screening questionnaire) were also assessed. Multivariable logistic regression and Cox proportional hazards were used to analyze the relationship between pain and 5-year mortality.

RESULTS

Of 5,703 participants, 4,694 (82.3%) had complete data for analysis; 1,663 of these (35.4%) reported moderate, severe, or very severe pain, and 1,343 (28.6%) had died at 5-year follow-up. Four hundred ninety-six of those who died (29.8%) reported moderate, severe, or very severe pain and 847 (27.9%) no or very mild pain. Multivariate logistic analysis found that individuals with moderate, severe, or very severe pain had lower odds of 5-year mortality than those with no or very mild pain (odds ratio=0.78, 95% confidence interval (CI)=0.66-0.92; P<.001). The risk of death was lower in persons reporting moderate or greater pain than in those with no or very mild pain (HR=0.85, 95% CI=0.75-0.96; P=.01). An interaction between pain and sex explained this effect. Men with pain were not significantly more likely than men without pain to die (HR=1.00, 95% CI=0.84-1.19; P=.99), whereas women without pain (HR=0.54, 95% CI=0.47-0.63; P<0.01) and women with pain (HR=0.40; CI=0.33-0.47; P<.01) had less risk of death than men without and with pain, respectively.

CONCLUSION

Older women with pain were less likely to die within 5 years than older women without pain, men in pain, or men without pain.

Economic and humanistic burden of post-trauma and post-surgical neuropathic pain among adults in the United States

Background

Neuropathic pain (NeP) can be chronic, debilitating, and can interfere with sleep, functioning, and emotional well being. While there are multiple causes of NeP, few studies have examined the disease burden and treatment patterns associated with post-traumatic/post-surgical (PTPS) NeP.

Objective

To characterize pain, health status, function, health care resource utilization, lost productivity, and costs among subjects with PTPS NeP in the United States.

Methods

This observational study enrolled 100 PTPS NeP subjects recruited during routine visits from general practitioner and specialist sites. Subjects completed a one-time questionnaire with validated measures of pain severity and pain interference, health status, sleep, anxiety and depression, productivity, and study-specific items on demographics, employment status, and out-of-pocket expenses. Investigators completed a case report form based on a 6-month retrospective chart review, recording subjects’ clinical characteristics as well as current and previous medications/treatments for NeP. Subjects were stratified into mild, moderate, and severe pain groups.

Results

Subjects’ demographic characteristics were: mean age of 54.9 years, 53% female, and 22% employed for pay. Mean pain severity score was 5.6 (0–10 scale), with 48% and 35% classified as having moderate and severe pain, respectively. The mean number of comorbidities increased with greater pain severity (P = 0.0009). Patient-reported outcomes were worse among PTPS NeP subjects with more severe pain, including pain interference with function, health state utility, sleep, and depression (P < 0.0001). Eighty-two percent of subjects were prescribed two or more NeP medications. The total mean annualized adjusted direct and indirect costs per subject were $11,846 and $29,617, respectively. Across pain severity levels, differences in annualized adjusted direct and indirect costs were significant (P < 0.0001).

Conclusion

PTPS NeP subjects reported high pain scores, which were associated with poor health utility, sleep, mood, and function, as well as high health care resource utilization and costs. The quality of life impact and costs attributable to PTPS NeP suggest an unmet need for effective and comprehensive management.

Burden of illness associated with painful diabetic peripheral neuropathy among adults seeking treatment in the US: results from a retrospective chart review and cross-sectional survey

BACKGROUND

The purpose of this study was to characterize the burden of illness among adult subjects with painful diabetic peripheral neuropathy (pDPN) seeking treatment in the US.

METHODS

This observational study recruited 112 subjects with pDPN during routine visits from general practitioner and specialist sites. Subjects completed a one-time questionnaire, which included demographics, symptom duration, health care resource use, out-of-pocket costs, employment status, and validated measures that assessed pain, functioning, sleep, anxiety and depression, health status, and productivity. Investigators completed a case report form based on a 6-month retrospective chart review to capture clinical information, pDPN-related treatments, and other pDPN-related health care resource use over the past 6 months. Annualized costs were extrapolated based on reported 6-month health care resource use.

RESULTS

The mean age of the subjects was 61.1 years, 52.7% were female, and 17.9% were in paid employment. The most common comorbid conditions were sleep disturbance/insomnia (43.8%), depressive symptoms (41.1%), and anxiety (35.7%). The mean pain severity score was 5.2 (0-10 scale), and 79.5% reported moderate or severe pain. The mean pain interference with function score was 5.0 (0-10 scale) overall, with 2.0 among mild, 5.1 among moderate, and 7.0 among severe. The mean Medical Outcomes Study sleep problems index score was 48.5 (0-100 scale). The mean health state utility score was 0.61. Among subjects employed for pay, mean overall work impairment was 43.6%. Across all subjects, mean overall activity impairment was 52.3%. In total, 81.3% were prescribed at least one medication for their pDPN; 50.9% reported taking at least one nonprescription medication. Adjusted mean annualized total direct and indirect costs per subject were $4841 and $9730, respectively. Outcomes related to pain interference with function, sleep, health status, activity impairment, prescription medication use, and direct and indirect costs were significantly worse among subjects with more severe pain (P < 0.0020).

CONCLUSION

Subjects with pDPN exhibited high pain levels, which were associated with poor sleep, function, and productivity. Health care resource utilization in pDPN was prevalent and costs increased with greater pain severity. The burden of pDPN was greater among subjects with greater pain severity.

Identification of patients with painful diabetic peripheral neuropathy who have a favorable cost profile with pregabalin treatment

OBJECTIVE

To characterize patient populations with favorable costs after the initiation of pregabalin for the treatment of painful diabetic peripheral neuropathy (pDPN) relative to duloxetine, gabapentin, and amitriptyline.

METHODS

Patients were identified from MarketScan having ≥ 1 claim for pDPN (ICD-9-CM codes 250.6 or 357.2) within 60 days of first prescription (index) for pregabalin, duloxetine, gabapentin, or amitriptyline in 2008 and continuous enrollment 12 months pre- and postindex. Pregabalin patients were propensity-score-matched to each comparator. Using cutoff values ≥ 80% proportion of days covered (PDC) and ≥ 65 years for age, pre- to postindex changes in healthcare costs were estimated for pregabalin vs. comparators.

RESULTS

Of 987 patients initiated on pregabalin, 349 matched to duloxetine; 987 to gabapentin; 276 to amitriptyline. The pre- to postindex changes in total healthcare costs were similar between cohorts: $3272 with pregabalin vs. $2290 with duloxetine (P = 0.5280); $3687 with pregabalin vs. $5498 with amitriptyline (P = 0.5863); $3869 with pregabalin vs. $4106 with gabapentin (P = 0.8303). For the high-age/high-PDC population, the pre- to postindex differences in mean total costs were significantly lower with pregabalin (P < 0.001) relative to comparators ($3573 vs. $8288 for duloxetine; $1423 vs. $3167 for gabapentin; $2285 vs. $6160 for amitriptyline).

CONCLUSIONS

The association of lower total costs among older individuals with pDPN who maintain high adherence to pregabalin therapy relative to key comparators suggests a pharmacoeconomic advantage of pregabalin in this population combined with a need for strategies promoting adherence.

Epidemiology of neuropathic pain and its impact on quality of life

Epidemiology is an important clinical tool in designing and evaluating management and prevention strategies, and is particularly relevant to neuropathic pain. However, there is a relative lack of accurate information available. In one sense, neuropathic pain describes a symptom or a mechanism, rather than a specific disease; on the other hand, there are sufficient similarities in the effects and response to treatment between different causes to make it worthwhile to consider neuropathic pain as a distinct condition. However, there are important specific disease-based factors that need to be considered separately. Estimates of prevalence that are based on specific causes of neuropathic pain tend to be lower (1-2%) than those that are based on reports of the classic symptoms (6-8%), and further methodological research is needed. All neuropathic pain is associated with poor general health, comparable with other severe chronic diseases. The importance of newly proposed risk factors, including genetic factors, still needs to be assessed at a population level.

Peripheral neuropathy: evidence-based treatment of a complex disorder

Peripheral neuropathy (PN) is a common and often progressive condition frequently seen in primary care. The chronic pain associated with PN, or neuropathic pain, can significantly diminish patients' quality of life and be challenging to treat.

Is treatment of postherpetic neuralgia in the community consistent with evidence-based recommendations?

Few studies have examined the extent to which treatment of patients with neuropathic pain in the community is consistent with evidence-based treatment recommendations. U.S. health care claims were used to identify patients who received a diagnosis of postherpetic neuralgia (PHN). The initial pharmacologic treatments and changes to these treatment regimens were categorized according to the International Association for the Study of Pain Neuropathic Pain Special Interest Group recommendations for first-, second-, and third-line treatment of neuropathic pain. The results indicated that the treatment of PHN was only partially consistent with these treatment recommendations. Of the patients diagnosed with PHN who were not already on a specified treatment, 70% began treatment with either a first-, second-, or third-line treatment or a not-recommended treatment, and 30% did not begin treatment with any of these medications. Only one-quarter of patients began treatment with a first-line medication, the same percentage that began treatment with either a third-line medication or a not-recommended treatment. There was a wide range of initial treatment durations, but the means and medians suggest that patients and clinicians often decide to change the initial treatment within 2 months, either by discontinuing it, replacing it with a new medication, or adding a new medication. Although there were generally shorter treatment durations with opioid analgesics and tramadol, these medications were more frequently used in beginning treatment than the other treatments. The results suggest that a considerable number of patients with PHN in the community are not receiving evidence-based treatment.

Costs of pregabalin or gabapentin for painful diabetic peripheral neuropathy

OBJECTIVE

To characterize and compare healthcare resource utilization and costs among patients with painful diabetic peripheral neuropathy (pDPN) newly prescribed pregabalin or gabapentin in a real-world clinical setting.

STUDY DESIGN

Retrospective cohort analysis using the MarketScan Commercial Claims and Encounters and Medicare Supplemental Databases (2007-2009).

METHODS

Patients with new prescriptions for pregabalin or gabapentin (index event) in 2008 and ≥1 healthcare encounter with an ICD-9 code for pDPN (250.6 or 357.2) within 30 days prior to the first prescription were identified and propensity score matched; continuous enrollment 12 months pre- and post-index was required. Pre- to post-index changes in 12-month all-cause and pDPN-attributable resource utilization and costs were compared between pregabalin and gabapentin using a difference-in-difference (DID) approach.

RESULTS

A total of 910 pregabalin patients (48.6% female; mean age 63.3 ± 12.1 years) were matched with 910 gabapentin patients (48.8% female; mean age 63.3 ± 12.1 years). The DID showed no significant differences between cohorts for pre- to post-index changes in any of the all-cause resource utilization categories. While prescription costs increased significantly more with pregabalin (DID -$563; p < 0.0001), the DID of $1603 for total healthcare costs per patient indicated that the pre- to post-index increases of $3081 for pregabalin and $4684 for gabapentin patients were comparable (p = 0.8474). Total pDPN-attributable healthcare costs were significantly higher with pregabalin (DID -$385; p < 0.0001), resulting from higher prescription costs (DID -$432; p < 0.0001). Limitations of this study include the inability to specifically link pDPN with medication prescribing; differences between groups despite propensity score matching; use of proxy measures for adherence parameters; and inability to capture efficacy outcomes.

CONCLUSIONS

Among patients initiating pregabalin or gabapentin, there were no significant differences between the drugs in the pre- to post-index changes in all-cause total healthcare costs, despite the increase in prescription costs for pregabalin.

Association of patient-rated severity with other outcomes in patients with painful diabetic peripheral neuropathy

OBJECTIVE

To evaluate the association of patient-reported severity of painful diabetic peripheral neuropathy (pDPN) with other outcomes in a European population of patients using the Adelphi Disease Specific Programme for pDPN (DSP III, 2008).

METHODS

The severity of patients' pDPN (mild, moderate, or severe) was rated independently by both patients and physicians. Relationships were evaluated between patient-reported pDPN severity and other patient-reported outcomes including pain, sleep, function, and work productivity. Physicians rated the severity of patients' pDPN (1 = mild, 2 = moderate, 3 = severe) and sleep interference.

RESULTS

Patient-reported data were available from 634 individuals (56.2% male, mean age 63 years) from France, Germany, Italy, and the UK, of whom only 22.2% reported that they were currently employed. pDPN severity was rated as mild, moderate, and severe by 22.2%, 60.9%, and 16.9% of the patients, respectively. There was a significant association between patient-rated and physician-rated pDPN severity (P < 0.0001), although there were discrepancies in agreement (kappa = 0.37, 95% confidence interval [CI] 0.31, 0.43; weighted kappa = 0.43, 95% CI 0.37, 0.48) among physician and patient ratings in a substantial proportion of patients across severity categories. Higher pDPN severity was associated with greater interference of daily function including sleep (P < 0.0001 for all pairwise comparisons). Among employed patients, percent of pDPN-related impairment while at work (presenteeism) and overall work impairment increased with greater pDPN severity, resulting in indirect costs that increased significantly with pDPN severity; $8266, $15,449, and $24,300 for mild, moderate, and severe pDPN, respectively (overall P < 0.001).

CONCLUSION

Severity of patient-rated pDPN was significantly associated with outcomes, including function and productivity; poorer function and lower productivity were reported at higher pDPN severity levels. Moreover, physicians rated pDPN severity different from patients in a substantial proportion of patients.