Composite Pain Index: Reliability, Validity, and Sensitivity of a Patient-Reported Outcome for Research

Sex-stratified association of variants in the serotonin 1A receptor gene with acute crisis pain among African American patients with sickle cell disease

Patients with sickle cell disease (SCD) experience pain in their daily lives. Both the acute and chronic pain phenotypes of this disease exhibit high variability, making pain management a challenge. The underlying reasons for the phenotypic variability are poorly understood. Given the importance of serotonergic neurotransmission in pain signaling, we aimed to explore the role of variants in the 5-HT1A receptor gene (HTR1A) on pain variability in SCD. Four variants (rs6449693, rs878567, rs6294, and rs10042486) in HTR1A were genotyped in a cohort of 131 African Americans with SCD. Acute and chronic pain were measured by the acute care utilization and the McGill Pain Questionnaire, respectively. Association analyses were performed for three genetic models (additive, dominant, and recessive). Three variants (rs6449693, rs6294, and rs10042486) in HTR1A showed significant association with crisis pain in both the additive and dominant models. Although the G allele of rs6449693 and the C allele of rs10042486 associated with lower acute crisis pain, the T allele of rs6294 associated with increased acute crisis pain. Sex-stratified analyses revealed that the associations of these three variants with acute pain were significant only in men, but not in women. Furthermore, the A allele rs878567 that did not reach statistical significance in the overall cohort showed a significant association with lower crisis pain in men. To our knowledge, as the first study to explore the role of HTR1A variants in sickle cell pain, we identified that four variants across the gene are associated with acute crisis pain in SCD in a sex-stratified manner.

Promise of Composite Pain Index as a single pain outcome for sickle cell disease across the lifespan

BACKGROUND

This study aimed to validate a Composite Pain Index (CPI) as a single pain outcome measure for sickle cell disease (SCD) across the lifespan from 8 years of age.

PROCEDURE

This prospective, cross-sectional study included 55 participants with SCD who completed the PAINReportIt tool and Adolescent Pediatric Pain Tool (APPT) in random order during outpatient visits to derive respective CPI scores for comparison.

RESULTS

Of the 55 participants with SCD, 46 (84%) had HgbSS, eight (15%) HgbSC, and one (2%) HgbSβ0+. The mean age of all participants was 17.5 ± 2.6 years, and 28 (51%) were female, 52 (95%) were Black, 42 (98%) were non-Hispanic, and 39 (71%) had a ninth grade or higher education. Correlation analyses between the APPT and PAINReportIt revealed positive associations for the number of pain sites (r = .57, p < .001), pain intensity (r = .46, p < .001), pain quality (r = .74, p < .001), and pain pattern (r = .34, p = .01). Patients' mean CPI scores derived from the PAINReportIt was slightly higher than the APPT; 34.2 (SD = 14.7) and 30.0 (SD = 19.0), respectively. Regression analyses showed that the APPT CPI significantly predicted the PAINReportIt CPI (B = .497, t(53) = 6.051, p < .001). This finding holds true even when accounting for the order of measurement or patient's age.

CONCLUSION

The initial validation of CPI as a single pain outcome measure represents a significant advancement in pain assessment for SCD. Further validation is warranted for the CPI as a measure is for both clinicians and researchers to enable longitudinal pain assessment from age 8 years across the lifespan as children age into adult care.

Single nucleotide polymorphisms and sickle cell disease-related pain: a systematic review

Background

Scientists have speculated genetic variants may contribute to an individual's unique pain experience. Although research exists regarding the relationship between single nucleotide polymorphisms and sickle cell disease-related pain, this literature has not been synthesized to help inform future precision health research for sickle cell disease-related pain. Our primary aim of this systematic review was to synthesize the current state of scientific literature regarding single nucleotide polymorphisms and their association with sickle cell disease-related pain.

Methods

Using the Prisma guidelines, we conducted our search between December 2021-April 2022. We searched PubMed, Web of Science, CINAHL, and Embase databases (1998-2022) and selected all peer-reviewed articles that included reports of associations between single nucleotide polymorphisms and sickle cell disease-related pain outcomes.

Results

Our search yielded 215 articles, 80 of which were duplicates, and after two reviewers (GG, JD) independently screened the 135 non-duplicate articles, we retained 22 articles that met the study criteria. The synthesis of internationally generated evidence revealed that this scientific area remains predominantly exploratory in nature, with only three studies reporting sufficient power for genetic association. Sampling varied across studies with a range of children to older adults with SCD. All of the included articles (n = 22) examined acute pain, while only nine of those studies also examined chronic pain.

Conclusion

Currently, the evidence implicating genetic variation contributing to acute and chronic sickle cell disease-related pain is characterized by modestly powered candidate-gene studies using rigorous SCD-pain outcomes. Effect sizes and directions vary across studies and are valuable for informing the design of future studies. Further research is needed to replicate these associations and extend findings with hypothesis-driven research to inform precision health research.

An alcohol dehydrogenase 7 gene polymorphism associates with both acute and chronic pain in sickle cell disease

Introduction: As the most distressing complication of sickle cell disease (SCD), pain is marked by considerable heterogenicity. In this study we explored the potential association of alcohol dehydrogenase 7 gene (ADH7) polymorphism rs971074 with sickle cell pain. Methods: We analyzed clinical phenotypes and the rs971074 single-nucleotide polymorphism in ADH7 by MassARRAY-iPlex analysis in a cohort of SCD patients. Results: The synonymous rs971074 was significantly associated with both acute and chronic pain in SCD. Patients with the minor T allele(s) recorded significantly more crisis episodes and severe chronic pain symptoms. Conclusion: Our study has identified the rs971074 minor T allele as a genetic biomarker potentially influencing acute and chronic pain. These findings may ultimately help inform strategies to develop precision pain therapies in SCD.

Candidate gene association study suggests potential role of dopamine beta-hydroxylase in pain heterogeneity in sickle cell disease

Introduction: Pain is a lifelong companion of individuals with sickle cell disease (SCD) and has a severe impact on their quality of life. Both acute crisis pain and chronic non-crisis pain exhibit high variability between individuals, making it difficult to effectively manage sickle cell-related pain. We investigated the role of dopamine beta-hydroxylase (DBH) gene polymorphisms on pain variability in SCD. DBH is a key enzyme in the catecholamine biosynthesis pathway that catalyzes the conversion of dopamine to norepinephrine, both of which are known mediators of pain and pain-related behaviors. Methods: Acute crisis pain-related utilization and non-crisis chronic pain scores of 131 African Americans with SCD were obtained. Results and discussion: Association analyses revealed that the T allele of upstream variant rs1611115 and downstream variant rs129882 correlated with higher severity of chronic pain in an additive model. On the other hand, the A allele of missense variant rs5324 associated with lower risk of both acute crisis pain and chronic pain. Similarly, the C allele of intronic variant rs2797849 was associated with lower incidence of acute crisis pain in the additive model. In addition, tissue-specific eQTL revealed that the T allele of rs1611115 correlated with decreased expression of DBH in the frontal cortex and anterior cingulate cortex (GTEx), and decreased expression of DBH-AS1 in blood (eQTLGen). Bioinformatic approaches predicted that rs1611115 may be altering a transcription factor binding site, thereby, contributing to its potential effect. Taken together, findings from this study suggest that potential functional polymorphisms of DBH may modulate pain perception in SCD.

Intraindividual pain variability metrics for youth with sickle cell disease: Relations to health outcomes

BACKGROUND

While the majority of pediatric sickle cell disease (SCD) research has used mean pain intensity as the only pain metric, recent evidence suggests this metric alone is inadequate in describing the intraindividual variability in SCD pain experiences and subsequent impact. There is limited information on other intraindividual pain metrics in youth with SCD, or how they relate to health outcomes in this population. The aims of this study were to describe differing patterns of intraindividual pain metrics derived from ecological momentary assessments (EMAs) of youth with SCD and to characterize the unique relationships between these metrics and health outcomes.

METHODS

Eighty-eight youth with SCD, aged 8-17 (mean age = 11.6), were recruited from three regional pediatric SCD clinics in the United States. At baseline, youth and their guardians reported on demographic and disease information. Then youth completed twice daily EMAs for up to 4 weeks. Pain metrics derived from EMA data were calculated including mean daily pain intensity (DP), SD-DP (standard deviation of DP), proportion of pain days (PPD), and 90th percentile of DP (p90). Pearson correlations were calculated between pain metrics and health outcomes.

RESULTS

High DP and SD-DP were correlated with more anxiety symptoms, while high SD-DP and p90 were correlated with more depression symptoms. High SD-DP was correlated with low self-esteem, and high DP and PPD were correlated with low sickle cell self-efficacy. For healthcare utilization due to pain, high p90 was correlated with more emergency department visits, while high DP, p90, and PPD were correlated with more healthcare contacts.

CONCLUSION

There are distinct associations between pain variability metrics beyond DP and health outcomes. Collectively, the patterns of associations suggest the utility of these pain metrics for determining risk in relation to specific health outcomes for youth with SCD.

Multidimensional Pain Characteristics in Older Adults with Chronic Venous Leg Ulcers

Objective: Pain affects wound healing, treatment, and quality of life because it has significant impacts on physical, psychological, and social well-being. Despite the fact that more than half of chronic venous leg ulcer (CVLU) patients experience mild-to-moderate pain, the multidimensional characteristics of CVLU pain are not well documented. The objective of this study was to describe the multidimensional pain characteristics, including the sensory, affective, cognitive, and behavioral dimensions, of CVLU before debridement. Approach: Participants (N = 40) were recruited from a wound clinic. We conducted a descriptive analysis of clinical data, including pain, wound, and demographic characteristics, collected at the first visit. Results: The mean age of participants was 70.8 ± 9.1 years, 22 (55%) participants were female, and 35 (87.5%) were white. Participants reported mean current pain intensity (2.9 ± 2.7), least (1.2 ± 2.2) and worst (4.8 ± 3.4) pain intensity in 24 h, and tolerable pain level (4.9 ± 2.64) on a 0-10 scale. They described pain as periodic (66.7%, n = 26) with multiple pain quality descriptors (5.4 ± 2.9). Their past pain treatments provided some pain relief (65%, n = 25). For 68% (n = 27), their pain was the same as they expected. Nearly all had a tendency not to tell others about their pain (95%, n = 38). Innovation: This study is the first to describe the multidimensional pain characteristics of patients with CVLU as measured with PAINReportIt. Conclusion: Patients with CVLU reported willingness to tolerate a relatively high level of pain and experience the level of pain they anticipate. Multidimensional pain assessment will assist clinicians to select individualized therapies to manage pain and improve quality of life for these patients.

Patient-Reported Outcomes Integrated Within an Electronic Medical Record in Patients With Head and Neck Cancer

PURPOSE

Patient-reported outcome (PRO) tools lead to clinical benefits, including improved overall survival for patients with cancer. However, routine implementation of PROs in clinical practice within the electronic medical record (EMR) by integrated health care delivery systems remains limited. We studied the use of a PRO tool for patients with head and neck cancer (HNC) integrated in an EMR at Kaiser Permanente in Northern California.

METHODS

Between August 2017 and December 2019, patients with newly diagnosed HNC were surveyed at baseline, then every 3 months using the Functional Assessment of Cancer Therapy-General 7 and Functional Assessment of Cancer Therapy-Head and Neck (version 4). A medical assistant performed a baseline survey on diagnosis and then notified patients electronically per surveillance protocol. Patients who did not respond to online PRO surveys could complete them via telephone or in-person appointments with medical assistants. Abnormal findings on PRO surveys were referred to appropriate members of the care team or the treating Otolaryngology-Head and Neck Surgery physicians.

RESULTS

Two hundred ninety patients received baseline surveys. Patients received up to a maximum of eight subsequent surveys. Of a total of 597 electronic surveys, 585 (97.9%) were completed. The percentage of patients completing each interval survey ranged from 92% to 100%. Multivariate Poisson regression analysis showed patients with English as their primary language and an online secure account were the most likely to complete surveys compared with those patients with non-English as a primary language and without an online account.

CONCLUSION

PRO tools can be effectively used within the EMR for patients with HNC with a high response rate provided there is strong engagement from a dedicated member of the care team. This has important implications for designing clinical trials and symptom monitoring in clinical practices that incorporate EMRs.

S100B single nucleotide polymorphisms exhibit sex-specific associations with chronic pain in sickle cell disease in a largely African-American cohort

BACKGROUND

Pain in sickle cell disease (SCD) is severe and multifaceted resulting in significant differences in its frequency and intensity among individuals. In this study, we examined the influence of S100B gene single nucleotide polymorphisms (SNP) on acute and chronic pain variability in SCD.

METHODS

Composite pain index (CPI) scores captured chronic pain. Painful crisis related emergency care utilization recorded acute pain incidence. Genotyping was performed using MassARRAY iPLEX platform.

RESULTS

Regression analysis revealed associations of increased CPI with rs9722 A allele in additive (p = 0.005) and dominant (p = 0.005) models. Rs1051169 G allele on the other hand was associated with decreased CPI in additive (p = 0.001), and dominant (p = 0.005) models. Sex-specific analysis found that these associations were significant in females but not males in this cohort. Linkage analysis identified two haploblocks. Block 1 (rs9983698-rs9722) haplotype T-A was associated with increased CPI (p = 0.002) while block 2 (rs1051169-rs11911834) haplotype G-G was associated with decreased CPI (p = 0.001). Both haplotypic associations were only significant in females. No association of S100B SNPs with utilization reached statistical significance.

CONCLUSIONS

S100B SNPs and haplotypes are associated with chronic pain in female, but not male, patients with SCD, implicating a potential role of S100B polymorphism in SCD pain heterogeneity in a sex-dependent manner.

Phenylethanolamine N-methyltransferase gene polymorphisms associate with crisis pain in sickle cell disease patients

Aim: Phenylethanolamine N-methyltransferase (PNMT) catalyzes the conversion of sympathetic neurotransmitter norepinephrine to epinephrine. We examined the association of PNMT polymorphisms with acute and chronic pain in sickle cell disease (SCD). Methods: Utilization of emergency care owing to painful crisis was used as a marker for acute pain in 131 patients with SCD. Results: rs876493 A allele, rs2934965 T allele and rs2941523 G allele were significantly associated with decreased utilization (p ≤ 0.05). rs876493 A allele showed association with utilization in females (p = 0.003), not males (p = 0.803). rs2934965 T allele and rs2941523 G allele were predicted to cause loss of putative transcription factor binding sites. This is the first report of the association of PNMT polymorphisms with acute crisis pain in SCD. Together with our previous findings in catechol-o-methyltransferase, polymorphisms in catecholamine metabolizing enzymes appear to primarily influence acute pain in SCD.

A Stepped-Wedge Randomized Controlled Trial: Effects of eHealth Interventions for Pain Control Among Adults With Cancer in Hospice

CONTEXT

Unrelieved cancer pain at the end of life interferes with achieving patient-centered goals.

OBJECTIVE

To compare effects of usual hospice care and PAINRelieveIt® on pain outcomes in patients and their lay caregivers.

METHODS

In a five-step, stepped-wedge randomized, controlled study, 234 patients (49% male, 18% Hispanic, 51% racial minorities) and 231 lay caregivers (26% male, 20% Hispanic, 54% racial minorities) completed pre-pain/post-pain measures. They received usual hospice care with intervention components that included a summary of the patient's pain data, decision support for hospice nurses, and multimedia education tailored to the patient's and lay caregiver's misconceptions about pain.

RESULTS

The intervention effect on analgesic adherence (primary outcome) was not significant. Post-test worst pain intensity was significantly higher for the experimental group, but the difference (0.70; CI = [0.12, 1.27]) was not clinically meaningful. There was nearly universal availability of prescriptions for strong opioids and adjuvant analgesics for neuropathic pain in both groups. Lay caregivers' pain misconceptions (0-5 scale) were significantly lower in the experimental group than the usual care group (mean difference controlling for baseline is 0.38; CI = [0.08, 0.67]; P = 0.01).

CONCLUSION

This randomized controlled trial was a negative trial for the primary study outcomes but positive for a secondary outcome. The trial is important for clearly demonstrating the feasibility of implementing the innovative set of interventions.

Randomized clinical trial of computerized PAINRelieveIt® for patients with sickle cell disease: PAINReportIt® and PAINUCope®

OBJECTIVE

To compare effects of a tailored multimedia education program versus usual-care on barriers to pain management of adult patients with SCD.

METHODS

Pretest/posttest randomized controlled trial (RCT) of 228 outpatients with SCD randomized to the tablet-based PAINUCope intervention focused on barriers to pain management, pain, and analgesic adherence or selection of games (control). Outcomes were barriers to pain management, pain, and analgesic adherence.

RESULTS

The barriers to pain management and pain scores did not change significantly from pretest to posttest for either condition. Changes in analgesic adherence rates from pretest to posttest were statistically significant for the intervention group (p = .046) but not for the usual care group (p = .419). The group difference was not statistically significant.

CONCLUSIONS

This first RCT of a tailored multimedia education intervention with adult patients with SCD did not significantly reduce the outcomes of interest compared to the control group. Findings provide insights for improving intervention delivery and reinforcement of patient behaviors.

PRACTICE IMPLICATIONS

Study redesign is warranted with modifications that include theoretical and methodological approaches and patient-centered delivery of the intervention that take advantage of recent technology developments.

Sensitivities to Thermal and Mechanical Stimuli: Adults With Sickle Cell Disease Compared to Healthy, Pain-Free African American Controls

Evidence supports^, but is inconclusive that sensitization contributes to chronic pain in some adults with sickle cell disease (SCD). We determined the prevalence of pain sensitization among adults with SCD pain compared with pain-free healthy adults. In a cross sectional, single session study of 186 African American outpatients with SCD pain (age 18-74 years, 59% female) and 124 healthy age, gender, and race matched control subjects (age 18-69 years, 49% female), we compared responses to standard thermal (Medoc TSA II) and mechanical stimuli (von Frey filaments). Although we observed no significant differences in thermal thresholds between controls and patients, patients with SCD had lower pain thresholds to mechanical stimuli and reported higher pain intensity scores to all thermal and mechanical stimuli at a non-painful body site. Compared with controls, about twice as many patients with SCD showed sensitization: 12% versus 23% at the anterior forearm site (P = .02), and 16% versus 32% across 3 tested sites (P = .004). Among patients with SCD, 18% exhibited some element of central sensitization. Findings indicate that persistent allodynia and hyperalgesia can be part of the SCD pain experience and should be considered when selecting therapies for SCD pain. PERSPECTIVE: Compared with matched healthy controls, quantitative sensory testing in adults with pain and sickle cell disease (SCD) demonstrates higher prevalence of sensitization, including central sensitization. The findings of allodynia and hyperalgesia may indicate neuropathic pain and could contribute to a paradigm shift in assessment and treatment of SCD pain.

Vasopressin SNP pain factors and stress in sickle cell disease

PURPOSE

Frequencies of single nucleotide polymorphisms (SNPs) from pain related candidate genes are available for individuals with sickle cell disease (SCD). One of those genes, the arginine vasopressin receptor 1A gene (AVPR1A) and one of its SNPs, rs10877969, has been associated with pain and disability in other pain populations. In patients with SCD, clinical factors such as pain and stress have been associated with increased health care utilization, but it is not known if the presence of the AVPR1A SNP plays a role in this observation. The study purpose was to explore the relationships between rs10877969 and self-reported pain, stress, and acute care utilization events among individuals with SCD.

METHODS

In a cross-sectional investigation of outpatients with SCD, participants completed PAINReportIt®, a computerized pain measure, to describe their pain experience and contributed blood or saliva samples for genetic analysis. We extracted emergency department and acute care utilization from medical records.

RESULTS

The SNP genotype frequencies (%) for this sample were CC 30 (28%), CT 44 (41%), TT 33 (31%). Acute care utilization and stress as an aggravator of pain were significantly associated with the rs10877969 genotype (p = .02 and p = .002, respectively). The CT genotype had the highest mean utilization and CC genotype was associated with not citing stress as a pain aggravator. Chronic pain was not associated with rs10877969 (p = .41).

CONCLUSION

This study shows that rs10877969 is related to indicators of stress and acute pain. Further research is recommended with other measures of stress and acute pain.

Sensory pain characteristics of vulvodynia and their association with nociceptive and neuropathic pain: an online survey pilot study

Supplemental Digital Content is Available in the Text.

Objectives:

To evaluate self-reported sensory pain scores of women with generalized vulvodynia (GV) and provoked vestibulodynia (PVD), characterize pain phenotypes, and assess feasibility of using the Internet for recruitment and data collection among women with vulvodynia.

Methods:

Descriptive online survey. Data collected using an online survey accessed via a link on the National Vulvodynia Association web site. Convenience sample, 60 women aged 18 to 45 years (mean = 32.7 ± 5.5); 50 white, 2 black/African American, 4 Hispanic/Latino, and 4 Native American/Alaskan Native, diagnosed with vulvodynia, not in menopause. Pain assessment and medication modules from PAINReportlt.

Results:

Women with GV (n = 35) compared to PVD (n = 25). Estimated mean pain sites (2.5 ± 1.4 vs 2.2 ± 1.0, P = 0.31), mean current pain (8.7 ± 1.4 vs 5.5 ± 4.0, P = 0.0008), worst pain (8.1 ± 1.8 vs 6.1 ± 3.6, P = 0.02), and least pain in the past 24 hours (4.4 ± 1.8 vs 2.0 ± 2.0, P < 0.0001). Average pain intensity (7.1 ± 1.2 vs 4.6 ± 2.9, P = 0.0003) on a scale of 0 to 10, mean number of neuropathic words (8.3 ± 3.6 vs 7.7 ± 5.0), and mean number of nociceptive words (6.9 ± 4 vs 7.5 ± 4.4). Nineteen (54%) women with GV compared to 9 (38%) with PVD were not satisfied with pain levels.

Conclusion:

Women with GV reported severe pain, whereas those with PVD reported moderate to severe pain. Pain quality descriptors may aid a clinician's decisions about whether to prescribe adjuvant drugs vs opioids to women with vulvodynia.

Beta2-Adrenergic Receptor Polymorphisms and Haplotypes Associate With Chronic Pain in Sickle Cell Disease

Pain in sickle cell disease (SCD) is severe, variable, and inadequately comprehended. The β2-adrenergic receptor (ADRB2) is critical in mediating neurotransmitter response in the sympathetic nervous system. In this association study, we examined 16 single nucleotide polymorphisms (SNPs) covering 5'-UTR and coding regions of ADRB2 for pain variability in SCD. Subjects recorded their non-crisis, baseline pain experience on a computerized tool from which we obtained chronic pain measurement score- composite pain index (CPI). Regression models yielded significant associations between chronic pain and seven SNPs. Non-synonymous SNP rs1042713 A allele (Arg16) caused a 5.73-fold decrease in CPI (p = 0.002). Allele A of rs12654778 and T of rs17778257 reduced CPI by a fold of 4.52 (p = 0.019), and 4.39 (p = 0.032), respectively. Whereas, in the 5' UTR, allele C of rs1042711, G of rs11168070, C of rs11959427, and C of rs1801704 increased CPI by a fold of 10.86 (p = 0.00049), 5.99 (p = 0.016), 5.69 (p = 0.023), and 5.26 (p = 0.031), respectively. Together, these SNPs accounted for 2-15% of CPI variance after adjusting for covariates. Moreover, these SNPs were in high linkage disequilibrium (LD) showing three LD blocks in our cohort. A 10-marker haplotype increased CPI by 11.5-fold (p = 0.000407). Thus, ADRB2 polymorphisms might contribute to chronic pain severity and heterogeneity in SCD.

Glucocorticoid receptor single nucleotide polymorphisms are associated with acute crisis pain in sickle cell disease

AIM

Pain in sickle cell disease patients is heterogeneous and genetic polymorphisms may predispose an individual to varied vulnerability to painful events. We studied the association of SNPs in the glucocorticoid receptor gene (NR3C1) with pain in sickle cell disease.

METHOD

Acute pain was scored as the number of utilizations due to crisis pain in a 12-month period. Chronic pain was calculated as the Composite Pain Index score.

RESULTS & CONCLUSION

rs33389 T allele (IRR = 1.53, p = 0.014 additive; IRR = 1.64, p = 0.011 recessive), rs2963155 G allele (IRR = 1.80, p < 0.001 additive; IRR = 2.25, p = 0.021 dominant; IRR = 2.07, p < 0.001 recessive) and rs9324918 C allele (IRR = 1.43, p = 0.021 additive) were associated with higher utilization rates, indicating the potential contribution of NR3C1 polymorphisms to acute pain heterogeneity in sickle cell disease.

Genetic variants of GCH1 associate with chronic and acute crisis pain in African Americans with sickle cell disease

The multidimensional nature of pain in sickle cell disease (SCD) has rendered its therapeutic management extremely challenging. In this study, we explored the role of five single nucleotide polymorphisms (SNPs) of candidate gene GCH1 in SCD pain. Composite pain index (CPI) scores and acute care utilization rates were used as phenotype markers. Rs8007267 was associated with chronic pain (additive model: B = -3.76, p = 0.037; dominant model: B = -5.61, p = 0.021) and rs3783641 (additive model: incident rate ratio [IRR] = 1.37, p = 0.024; recessive model: IRR = 1.81, p = 0.018) with utilization rate. These associations persisted when subjects with HbSS and HbSβ° genotype only were analyzed. We also identified two haploblocks (rs10483639[G>C]-rs752688[C>T]-rs4411417[T>C] and rs3783641[T>A]-rs8007267[T>C]) with SNPs in high linkage disequilibrium. Of these, haplotype T-C of haploblock rs3783641-rs8007267 showed significant association with rate of utilization (odds ratio [OR] = 0.31, p = 0.001). Our study indicates potential contribution of GCH1 polymorphisms to the variability of pain in African Americans with SCD.

Transient receptor potential polymorphism and haplotype associate with crisis pain in sickle cell disease

AIM

Episodes of acute pain crisis contribute to considerable morbidity and mortality in sickle cell disease (SCD). Incomprehensive understanding of the underlying pain heterogeneity results in inadequate pain management. The transient receptor potential (TRP) family of voltage-gated ion channels acts as sensory transducers of diverse noxious stimuli. We performed an association study of polymorphisms in candidate genes TRPV1 and TRPA1 with pain in SCD patients.

METHODS

Utilization rate, in other words, number of emergency department/acute care center admissions over 12 months as a result of pain crisis, served as a marker for acute pain.

RESULTS & CONCLUSION

We identified that rs920829 (incident rate ratio = 1.44, p = 0.027 additive; IRR=1.68, p=0.008 recessive models of negative binomial regression) and the CGAGG haplotype of TRPA1 (odds ratio = 0.218, p = 0.009) were significantly associated with utilization rate, suggesting that TRPA1 gene polymorphisms may influence acute pain crisis in SCD.

IL1A rs1800587 associates with chronic noncrisis pain in sickle cell disease

AIM

Pain is prevalent in sickle cell disease (SCD) patients who display great heterogeneity in pain severity and frequency. Hypothesizing that inflammatory factors are involved in the pathogenesis of SCD pain, we focused on the IL1A C/T polymorphism rs1800587 that is an SNP located in a cis-transcriptional regulatory region.

METHODS

We genotyped IL1A rs1800587 and performed association studies with phenotype data obtained by a multidimensional pain assessment tool using the PAINReportIt^® Questionnaire.

RESULTS

Each T allele was associated with a 3.9 increase in composite pain index score (p = 0.04) as determined by multiple linear regression.

CONCLUSION

IL1A rs1800587 may influence chronic pain in SCD.

A randomized controlled pilot study feasibility of a tablet-based guided audio-visual relaxation intervention for reducing stress and pain in adults with sickle cell disease

AIM

To test feasibility of a guided audio-visual relaxation intervention protocol for reducing stress and pain in adults with sickle cell disease.

BACKGROUND

Sickle cell pain is inadequately controlled using opioids, necessitating further intervention such as guided relaxation to reduce stress and pain.

DESIGN

Attention-control, randomized clinical feasibility pilot study with repeated measures.

METHODS

Randomized to guided relaxation or control groups, all patients recruited between 2013-2014 during clinical visits, completed stress and pain measures via a Galaxy Internet-enabled Android tablet at the Baseline visit (pre/post intervention), 2-week posttest visit and also daily at home between the two visits. Experimental group patients were asked to use a guided relaxation intervention at the Baseline visit and at least once daily for 2 weeks. Control group patients engaged in a recorded sickle cell discussion at the Baseline visit. Data were analysed using linear regression with bootstrapping.

RESULTS

At baseline, 27/28 of consented patients completed the study protocol. Group comparison showed that guided relaxation significantly reduced current stress and pain. At the 2-week posttest, 24/27 of patients completed the study, all of whom reported liking the study. Patients completed tablet-based measures on 71% of study days (69% in control group, 72% in experiment group). At the 2-week posttest, the experimental group had significantly lower composite pain index scores, but the two groups did not differ significantly on stress intensity.

CONCLUSION

This study protocol appears feasible. The tablet-based guided relaxation intervention shows promise for reducing sickle cell pain and warrants a larger efficacy trial.

TRIAL REGISTRATION

The ClinicalTrials.gov Identifier is: NCT02501447.

Satisfied or not satisfied: pain experiences of patients with sickle cell disease

AIMS

To examine the relationship between pain and satisfaction in patients with sickle cell disease.

BACKGROUND

Frequency and severity of unrelieved sickle cell pain are positively associated with mortality. Yet, information is scarce on whether sickle cell patients are satisfied with their pain level.

DESIGN

A cross-sectional, correlational analysis of baseline data from a randomized clinical trial.

METHODS

A randomized sample of adult outpatients was recruited between February 2007-March 2011. Patients completed the PAINReportIt(®) , containing measures of pain, satisfaction and socio-demographics. We analysed data using Kendall's rank correlations, analysis of variance, Tukey-Kramer post hoc tests, Fisher's tests and proportional odds logistic regression.

RESULTS

There were statistically significant correlations between pain outcomes and satisfaction with pain level, but average pain intensity more strongly discriminated groups based on satisfaction with pain level. Among pain variables bivariately associated with patient satisfaction with pain level, only pain expectation maintained its significant relationship with satisfaction with pain level when average pain intensity was controlled. A smaller percentage of our sickle cell patients reported moderate to severe pain intensity (28%) or high composite pain index (39%), while reporting being satisfied with pain their level than reported in earlier studies using different measures and populations (70-94%).

CONCLUSION

Satisfaction with pain level was an unambiguous measure of patient satisfaction and a promising indicator of pain that did not show the paradoxical relationship between satisfaction and pain seen with past measures.

Outpatient pain predicts subsequent one-year acute health care utilization among adults with sickle cell disease

CONTEXT

Patient demographic and clinical factors have known associations with acute health care utilization (AHCU) among patients with sickle cell disease (SCD), but it is unknown if pain measured predominantly in an outpatient setting is a predictor of future AHCU in patients with SCD.

OBJECTIVES

To determine whether multidimensional pain scores obtained predominantly in an outpatient setting predicted subsequent 1-year AHCU by 137 adults with SCD and whether the pain measured at a second visit also predicted AHCU.

METHODS

Pain data included the Composite Pain Index (CPI), a single score representative of a multidimensional pain experience (number of pain sites, intensity, quality, and pattern). Based on the distribution of AHCU events, we divided patients into three groups: 1) zero events (zero), 2) 1 to 3 events (low), or 3) 4 to 23 events (high).

RESULTS

The initial CPI scores differed significantly by the three groups (F(2,134) = 7.38, P = 0.001). Post hoc comparisons showed that the zero group had lower CPI scores than both the low (P < 0.01) and high (P < 0.001) groups. In multivariate overdispersed Poisson regression analyses, age and CPI scores (at both measurement times) were statistically significant predictors of utilization events. Pain intensity scores at both measurement times were significant predictors of utilization, but other pain scores (number of pain sites, quality, and pattern) were not.

CONCLUSION

Findings support use of outpatient CPI scores or pain intensity and age to identify at-risk young adults with SCD who are likely to benefit from improved outpatient pain management plans.

Adolescent pediatric pain tool for multidimensional measurement of pain in children and adolescents

Very few multidimensional tools are available for measurement of pain in children and adolescents. We critically reviewed the scientific literature to examine the psychometrics and utility of the Adolescent Pediatric Pain Tool (APPT), a multidimensional self-report tool that evaluates the intensity, location, and quality (including affective, evaluative, sensory, and temporal) dimensions of pain. The APPT is available in English and Spanish for children and adolescents, and was modeled after the McGill Pain Questionnaire in adults. We found good evidence for construct validity, reliability, and sensitivity of the APPT for the measurement of pediatric pain. The APPT was used to measure pain in children with different conditions, such as cancer, sickle cell disease, orthopedic, traumatic injuries, and allergy testing. Although the APPT was designed to assess the multiple dimensions of pain, the majority of the reports included results only for the intensity ratings. Unlike the numerical and pediatric faces rating scales, which are widely used in clinical practice and research, the APPT is not limited to the single dimension of pain intensity. It measures multiple dimensions, and may be able to discriminate between nociceptive and neuropathic pain. The APPT is one of a few multidimensional pain measures that can help to advance the science of pediatric pain and its management. When the APPT is used in practice or research, the multiple dimensions of pain may be characterized and compared in different painful conditions. It may guide the use of multimodal interventions in children and adolescents with a variety of pain conditions.