Meta-analysis is a method to obtain a weighted average of results from various studies. In addition to pooling effect sizes, meta-analysis can also be used to estimate disease frequencies, such as incidence and prevalence. In this article we present methods for the meta-analysis of prevalence. We discuss the logit and double arcsine transformations to stabilise the variance. We note the special situation of multiple category prevalence, and propose solutions to the problems that arise. We describe the implementation of these methods in the MetaXL software, and present a simulation study and the example of multiple sclerosis from the Global Burden of Disease 2010 project. We conclude that the double arcsine transformation is preferred over the logit, and that the MetaXL implementation of multiple category prevalence is an improvement in the methodology of the meta-analysis of prevalence.

Meta-analysis of prevalence

Prevalence of pain in patients with breast cancer post-treatment: A systematic review

Background The prevalence and intensity of persistent post-surgical pain (PPSP) after breast cancer surgery are uncertain. We conducted a systematic review and meta-analysis to further elucidate this issue. Methods We searched MEDLINE, Embase, CINAHL, and PsycINFO, from inception to November 2018, for observational studies reporting persistent pain (≥3 months) after breast cancer surgery. We used random-effects meta-analysis and the Grading of Recommendations, Assessment, Development and Evaluations approach to rate quality of evidence. Results We included 187 observational studies with 297 612 breast cancer patients. The prevalence of PPSP ranged from 2% to 78%, median 37% (inter-quartile range: 22–48%); the pooled prevalence was 35% (95% confidence interval [CI]: 32–39%). The pooled pain intensity was 3.9 cm on a 10 cm visual analogue scale (95% CI: 3.6–4.2 cm). Moderate-quality evidence supported the subgroup effects of PPSP prevalence for localized pain vs any pain (29% vs 44%), moderate or greater vs any pain (26% vs 44%), clinician-assessed vs patient-reported pain (23% vs 36%), and whether patients underwent sentinel lymph node biopsy vs axillary lymph node dissection (26% vs 43%). The adjusted analysis found that the prevalence of patient-reported PPSP (any severity/location) was 46% (95% CI: 36–56%), and the prevalence of patient-reported moderate-to-severe PPSP at any location was 27% (95% CI: 10–43%). Conclusions Moderate-quality evidence suggests that almost half of all women undergoing breast cancer surgery develop persistent post-surgical pain, and about one in four develop moderate-to-severe persistent post-surgical pain; the higher prevalence was associated with axillary lymph node dissection. Future studies should explore whether nerve sparing for axillary procedures reduces persistent post-surgical pain after breast cancer surgery.

Prevalence and intensity of persistent post-surgical pain following breast cancer surgery: a systematic review and meta-analysis of observational studies.

Nerve injury during breast cancer surgery can cause neuropathic pain (NP). It is not known why some, but not all, patients develop chronic postsurgical neuropathic pain (CPSNP) after the same nerve injury. In this study, we examined 251 breast cancer survivors with surgeon-verified intercostobrachial nerve resection to identify factors that associate with CPSNP. The patients were recruited from a previous study of 1000 women treated for breast cancer in 2006 to 2010. This enabled us to analyze preoperative factors that associate with future CPSNP. The patients were re-examined in 2014 to 2016 to diagnose CPSNP using the revised NP diagnostic criteria. Preoperative assessments were pain in the area to be operated on, any chronic pain condition, depressive symptoms, anxiety, sleep, and experimental cold pain sensitivity using the cold pressor test (CPT). Follow-up assessments were CPT, psychological factors, sleep, any chronic pain, and basic laboratory tests. One hundred thirty-seven (55%) patients with intercostobrachial nerve resection fulfilled CPSNP diagnostic criteria after 4 to 9 years. Of them, 30 patients (22%) had moderate to severe pain in self-reports and 86 (63%) presented moderate to severe evoked pain at examination. Preoperative pain in the surgical area, other chronic pains, and breast-conserving surgery were associated with future CPSNP. Other chronic pains, increased psychological burden, and insomnia, both before surgery and at the follow-up, were associated with CPSNP. Preoperative CPT did not associate with future CPSNP. Patients with established CPSNP showed increased pain sensitivity in CPT and higher levels of inflammatory markers, suggesting that central sensitization and inflammation may associate with the maintenance of CPSNP.

What makes surgical nerve injury painful? A 4-year to 9-year follow-up of patients with intercostobrachial nerve resection in women treated for breast cancer.

Advanced breast cancer is characterized by many physical manifestations with the potential to undermine the quality of life (most related to the cancer and some to treatments), as well as substantial impact on psychosocial well-being. Patients with advanced breast cancer and their families have complex needs that have to be addressed in order to minimize severe distress and deterioration in the quality of life of patients and their family members. This task requires the full engagement of an interdisciplinary approach to palliative care with strong emphasis on the assessment of needs and anticipated needs, patient expectations, skilled therapeutics, and commitment to continuity of care. In this review, we address four issues: 1) organizational and conceptual issues in palliative care of patients with breast cancer, 2) common physical symptoms among patients with breast cancer and their management, 3) common psychological issues among patients with breast cancer, and 4) common challenging palliative care problems in breast cancer.

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Palliative care: needs of advanced breast cancer patients.

Pain is common, but often poorly managed after breast cancer treatment. Screening questionnaires and the Neuropathic Pain Special Interest Group (NeuPSIG) criteria are 2 clinical approaches used to determine whether pain has neuropathic components, which may enable better pain management. The aims of this review were (1) to synthesise data from the literature on neuropathic pain prevalence in women after breast cancer treatment; (2) to investigate whether the prevalence of neuropathic pain differed between studies using screening questionnaires and the NeuPSIG criteria. We searched for studies that administered a validated neuropathic pain screening questionnaire and/or the NeuPSIG criteria to women treated for early-stage (I-III) breast cancer. Thirteen studies using screening questionnaires (N = 3792) and 3 studies using components of the NeuPSIG criteria (N = 621) were included. Meta-analyses were conducted for questionnaire data but not for NeuPSIG criteria data because of inadequate homogeneity. Among all participants treated for early-stage breast cancer, pooled prevalence estimates (95% confidence interval) ranged between 14.2% (8.3-21.4) and 27.2% (24.7-88.4) for studies using screening questionnaires; studies using NeuPSIG criteria reported prevalence rates from 24.1% to 31.3%. Among those who reported pain after treatment, the pooled prevalence estimate (95% confidence interval) of neuropathic pain from screening questionnaires ranged from 32.6% (24.2-41.6) to 58.2% (24.7-88.4); studies using NeuPSIG criteria reported prevalence rates from 29.5% to 57.1%. These prevalence estimates are higher than those reported for other types of cancer, and emphasise the need to assess the contribution of neuropathic pain after breast cancer treatment. Trial registration PROSPERO registration CRD42015029987.

The prevalence of neuropathic pain is high after treatment for breast cancer: a systematic review.

Increasing air pollution is common around the world, but the impacts of outdoor air pollution exposure on atopic dermatitis (AD) are unclear. We synthesized the current global epidemiologic evidence for air pollution exposure and associated medical visits for AD among adults and children. This review followed PRISMA guidelines, and searches were conducted on PubMed, MEDLINE, Web of Science, and EMBASE databases. The searches yielded 390 studies, and after screening, 18 studies around the world with at least 5,197,643 medical visits for AD were included for the final analysis. We found that exposure to particulate matter less than 2.5 microns in diameter (PM2.5 ) [(10/11) of studies], particulate matter less than 10 microns in diameter (PM10 ) (11/13), nitrogen dioxide (NO2 ) (12/14), and sulfur dioxide (SO2 ) (10/13) was positively associated with AD visits. Results were equivocal for ozone [(4/8) of studies reported positive association] and limited for carbon monoxide [(1/4) of studies reported positive association]. When stratifying results by patient age, patient sex, and season, we found that the associations with particulate matter, NO2 , and O3 may be affected by temperature. Exposure to selected air pollutants is associated with AD visits, and increasingly poor air quality may increase global health care use for AD.

Edwin Chee

Papers

The prevalence of neuropathic pain is high after treatment for breast cancer: a systematic review.

Air Pollution and Health Care Use for Atopic Dermatitis: A Systematic Review.