Osama A. Tashani

The prevalence of chronic pain with an analysis of countries with a Human Development Index less than 0.9: a systematic review without meta-analysis.

Abstract Background: To date, there are no systematic reviews of epidemiological studies of chronic pain in the developing world. Aim: To estimate the prevalence of chronic pain worldwide paying particular attention to data from countries with a Human Development Index (HDI) of less than 0.9. Methods: A literature search was conducted for cross-sectional surveys of chronic pain (≥3 months) in the adult general population using Medline, Embase, CINAHL, SportDiscus, Sciencedirect, CAS ILLUMINA, Academic search complete, PsycINFO and AMED. Forty-eight studies were identified and 29 of these were excluded because they surveyed children, the elderly or were longitudinal studies. Results: Weighted mean ± SD prevalence of chronic pain worldwide was 30.3% ± 11.7% (19 studies, 65 surveys, 34 countries, 182,019 respondents). There was no correlation between HDI and prevalence. In countries with a HDI < 0.9 prevalence was 33.9% ± 14.5% and significantly higher than prevalence in countries with a HDI of ≥0.9 (29.9% ± 12.7%), although removal of a large study that may have included a sample of individuals with comorbidities reduced the worldwide estimate to 28.0% ± 11.8% (47 surveys, 33 countries, 139,770 participants). Interestingly, the estimate of countries with a HDI < 0.9 to 24.8% ± 8.9% (7 surveys, 7 countries, 6122 participants) became significantly lower than the estimate of countries with a HDI ≥ 0.9 which was 28.1% ± 11.6% (40 surveys, 21 countries, 133,648 participants). Conclusion: The review provides further evidence that the prevalence of chronic pain in the general population is high. However, there was insufficient reliable data to estimate with any certainty the prevalence of chronic pain in countries with an HDI < 0.9 with variability in estimates between surveys being of concern. Subtle differences in review and survey methodology appeared to impact markedly on estimates. There is a need for epidemiological studies that estimate the prevalence of chronic pain in developing countries to determine the scale of the problem.

Gender role affects experimental pain responses: A systematic review with meta‐analysis

Gender role refers to the culturally and socially constructed meanings that describe how women and men should behave in certain situations according to feminine and masculine roles learned throughout life. The aim of this meta‐analysis was to evaluate the relationship between gender role and experimental pain responses in healthy human participants. We searched computerized databases for studies published between January 1950 and May 2011 that had measured gender role in healthy human adults and pain response to noxious stimuli. Studies were entered into a meta‐analysis if they calculated a correlation coefficient (r) for gender role and experimental pain. Searches yielded 4465 ‘hits’ and 13 studies were eligible for review. Sample sizes were 67–235 participants and the proportion of female participants was 45–67%. Eight types of gender role instrument were used. Meta‐analysis of six studies (406 men and 539 women) found a significant positive correlation between masculine and feminine personality traits and pain threshold and tolerance, with a small effect size (r = 0.17, p = 0.01). Meta‐analysis of four studies (263 men and 297 women) found a significant negative correlation between gender stereotypes specific to pain and pain threshold and tolerance, with a moderate effect size (r = −0.41, p < 0.001). In conclusion, individuals who considered themselves more masculine and less sensitive to pain than the typical man showed higher pain thresholds and tolerances. Gender stereotypes specific to pain scales showed stronger associations with sex differences in pain sensitivity response than masculine and feminine personality trait scales.

Effects of ethnicity and gender role expectations of pain on experimental pain: a cross-cultural study.

Gender role expectations of pain (GREP) have been shown to mediate sex differences in experimental pain. Few studies have investigated the role of ethnicity in shaping GREP. The aim of this study was to examine interactions between ethnicity and GREP on experimentally induced pressure and ischaemic pain in Libyan and white British students in their respective countries.

Translation and Linguistic Validation of the Self‐Completed Leeds Assessment of Neuropathic Symptoms and Signs (S‐LANSS) Scale for Use in a Libyan Population

Background:  The Leeds Assessment of Neuropathic Symptoms and Signs (LANSS) pain scale is used to identify pain of neuropathic origin and has been validated as a self‐completed tool (S‐LANSS). We translated the S‐LANSS into Arabic and evaluated its reliability and linguistic validity for use by Libyan people.

Avicenna’s concept of pain

Ibn Sina (Latin name – Avicenna, 980–1037) is a famous Muslim physician who wrote The Canon of Medicine. Pain-related writings within The Canon were identified and analysed and compared to Galen and Modern Pain Theory. We found evidence in The Canon that Avicenna challenged Galens concept of pain. Galen insisted that injuries (breach of continuity) were the only cause of pain. In contrast, Avicenna suggested that the true cause of pain was a change of the physical condition (temperament change) of the organ whether there was an injury present or not. Avicenna extended Galens descriptions of 4 to 15 types of pain and used a terminology that is remarkably similar to that used in the McGill Pain Questionnaire.

Gender role expectations of pain mediate sex differences in cold pain responses in healthy Libyans.

Previous studies found a relationship between response to experimentally‐induced pain and scores for the gender role expectations of pain (GREP) questionnaire. Findings were similar in individuals from America, Portugal and Israel suggesting that gender role expectations may be universal. The aim of this study was to translate and validate Arabic GREP using Factor Analysis and to investigate if sex differences to cold‐pressor pain in healthy Libyan men and women are mediated through stereotypical social constructs of gender role expectations and/or pain‐related anxiety. One hundred fourteen university students (58 women) underwent two cycles of cold pressor pain test to measure pain threshold, tolerance, intensity, and unpleasantness. Participants also completed the Arabic GREP questionnaire and the Pain Anxiety Symptom Scale‐Short form (PASS‐20). It was found that Libyan men had higher pain thresholds and tolerances than women (mean difference, 95% CI: threshold = 4.69 (s), −0.72 to 10.1, p = 0.005; tolerance = 13.46 (s), 0.5–26.4, p = 0.018). There were significant differences between sexes in 6 out of 12 GREP items (p < 0.004 after Bonferonni adjustment). The results of mediational analysis showed that GREP factors were the mediators of the effects of sex on pain threshold (z = −2.452, p = 0.014 for Self Sensitivity); (z = −2.563, p = 0.01, for Self Endurance) and on pain tolerance (z = −2.538, p = 0.01 for Self Endurance). In conclusion, sex differences in response to pain were mediated by gender role expectations of pain but not pain‐related anxiety.

A Cochrane systematic review of acupuncture for cancer pain in adults

Background Cancer-related pain is a significant and debilitating problem. Non-pharmacological treatments such as acupuncture may have an adjunctive role in controlling pain without the undesirable side effects of drug regimens and yet the evidence base remains limited. Objectives The main objective of this systematic review was to evaluate the effectiveness of acupuncture in the management of cancer-related pain in adults. Subgroup analyses were planned for acupuncture dose and for the outcome of studies investigating acupuncture for cancer-induced bone pain. Methods Six electronic databases were searched, including the Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE, PsycINFO, AMED and SPORTDiscus. Studies included in the review were randomised controlled trials investigating the use of acupuncture for cancer pain using pain as a primary outcome measure. In total, 253 published references were identified but only three studies met the inclusion criteria and were included in the final review. Results Of the three included studies, only one was judged to be of high methodological quality and showed auricular acupuncture to be superior to placebo acupuncture and ear seeds at placebo points. However, the study was relatively small and blinding was compromised. The two low-quality studies gave positive results in favour of acupuncture for cancer pain, but these results should be viewed with caution due to methodological limitations, small sample sizes, poor reporting and inadequate analysis. Conclusion There is insufficient evidence to judge whether acupuncture is effective in treating cancer pain in adults.

Age-related changes in pain sensitivity in healthy humans: A systematic review with meta-analysis

Literature suggests that pain perception diminishes in old age. The most recent review used search strategies conducted over a decade ago and concluded that study findings were equivocal. The aim of this systematic review, with meta‐analysis, was to determine age‐related changes in pain sensitivity in healthy pain‐free adults, children and adolescents. A search of PubMed, Science Direct, and PsycINFO identified studies that compared pain sensitivity response to noxious stimuli at different time points in the lifespan of healthy individuals. Selected studies were assessed for methodological quality and data pooled and meta‐analysed. Publication bias was tested using Funnel plots. Twelve studies were included in the review (study sample sizes 30–244 participants). Seven of nine studies found statistically significant differences in pain sensitivity response between old (mean ± SD 62.2 ± 3.4 to 79 ± 4 years) and younger adults (22 ± 1.5 to 39.1 ± 8.8 years), but the direction of change was inconsistent. Meta‐analysis found that pressure pain threshold was lower in old adults compared with younger adults (p = 0.018, I2 = 60.970%). There were no differences in contact heat pain thresholds between old and younger adults (p = 0.0001, I2 = 90.23%). Three studies found that younger children (6–8.12 years) were more sensitive to noxious stimuli than older children (9–14 years). Methodological quality of studies was high, with a low risk of publication bias. There was substantial statistical and methodological heterogeneity. There is tentative evidence that pressure pain threshold was lower in old adults compared with younger adults, with no differences in heat pain thresholds. Further studies are needed.

Prevalence of chronic pain among Libyan adults in Derna City: a pilot study to assess the reliability, linguistic validity, and feasibility of using an Arabic version of the structured telephone interviews questionnaire on chronic pain.

There are few studies estimating the prevalence of chronic pain in countries from the Middle East. We translated the Structured Telephone Interviews Questionnaire on Chronic Pain from English into Arabic and assessed its reliability and linguistic validity before using it in a telephone survey in Libya to gather preliminary prevalence data for chronic pain. Intraclass correlations for scaled items were high, and there were no differences in answers to nominal items between the first and second completions of the questionnaire. One hundred and 4 individuals participated in a telephone survey. The prevalence of chronic pain was 25.0% (95% CI, 16.7% to 33.3%) and 50.0% (95% CI: 30.8% to 69.2) of the participants with chronic pain scored ≥ 12 on the Arabic S‐LANSS. Mean ± SD duration of pain was 2.8 ± 1.2 years, and pain was more frequent in women (P = 0.02). 53.8% of participants had taken prescription medication for their pain, and 76.9% had used nondrug methods of treatment including traditional Libyan methods such as Kamara, a local herbal concoction. Eighty percent believed that their doctor would rather treat their illness than their pain, and 35% reported that their doctor did not think that their pain was a problem. Some participants complained that the questionnaire was too long with a mean ± SD call duration of 20 ± 5.4 minutes. We conclude that the Arabic Structured Telephone Interviews Questionnaire on Chronic Pain was reliable and linguistically valid and could be used in a large‐scale telephone survey on the Libyan population. Our preliminary estimate of prevalence should be considered with caution because of the small sample size.

The prevalence of chronic pain in developing countries.

83 ISSN 1758-1869 10.2217/PMT.12.83