Weighted metrics are required when evaluating the performance of prediction models in nested case–control studies

Background: Nested case–control (NCC) designs are efficient for developing and validating prediction models that use expensive or difficult-to-obtain predictors, especially when the outcome is rare. Previous research has focused on how to develop prediction models in this sampling design, but little attention has been given to model validation in this context. We therefore aimed to systematically characterize the key elements for the correct evaluation of the performance of prediction models in NCC data. Methods: We proposed how to correctly evaluate prediction models in NCC data, by adjusting performance metrics with sampling weights to account for the NCC sampling. We included in this study the C-index, threshold-based metrics, Observed-to-expected events ratio (O/E ratio), calibration slope, and decision curve analysis. We illustrated the proposed metrics with a validation of the Breast and Ovarian Analysis of Disease Incidence and Carrier Estimation Algorithm (BOADICEA version 5) in data from the population-based Rotterdam study. We compared the metrics obtained in the full cohort with those obtained in NCC datasets sampled from the Rotterdam study, with and without a matched design. Results: Performance metrics without weight adjustment were biased: the unweighted C-index in NCC datasets was 0.61 (0.58–0.63) for the unmatched design, while the C-index in the full cohort and the weighted C-index in the NCC datasets were similar: 0.65 (0.62–0.69) and 0.65 (0.61–0.69), respectively. The unweighted O/E ratio was 18.38 (17.67–19.06) in the NCC datasets, while it was 1.69 (1.42–1.93) in the full cohort and its weighted version in the NCC datasets was 1.68 (1.53–1.84). Similarly, weighted adjustments of threshold-based metrics and net benefit for decision curves were unbiased estimates of the corresponding metrics in the full cohort, while the corresponding unweighted metrics were biased. In the matched design, the bias of the unweighted metrics was larger, but it could also be compensated by the weight adjustment. Conclusions: Nested case–control studies are an efficient solution for evaluating the performance of prediction models that use expensive or difficult-to-obtain biomarkers, especially when the outcome is rare, but the performance metrics need to be adjusted to the sampling procedure.</p

Long-Term Use of Nonsteroidal Anti-inflammatory Drugs Decreases the Risk of Cutaneous Melanoma: Results of a United States Case–Control Study

Experimental and observational studies continue to demonstrate conflicting results regarding the role of several commonly used drugs as melanoma chemopreventive agents. This case–control study was designed to assess the associations between cutaneous melanoma (CM) and exposure to nonsteroidal anti-inflammatory drugs (NSAIDs) and statins in current users. A total of 400 CM and 600 eligible age- and gender-matched community-based controls were prospectively recruited and interviewed. We assessed participants’ demographic characteristics, CM risk factors, and current and previous use of medications. Multivariable conditional logistic regression models were used to estimate adjusted odds ratios (ORs) and 95% confidence intervals (CIs) for associations between NSAIDs and/or aspirin (ASA), statin exposure, and CM risk. Half of the subjects were men (mean age 60 years). After adjusting for confounders, use of any type of NSAIDs for more than 5 years significantly reduced the risk of melanoma development compared with the low-exposure group (adjusted OR=0.57; 95% CI=0.43–0.77). Subgroup analyses showed that the observed risk reduction was primarily driven by continuous ASA use (>5 years adjusted OR=0.51, 95% CI=0.35–0.75). No significant protective effect was observed with statin exposure (OR=0.97, 95% CI=0.73–1.29). Long-term use of NSAIDs, especially ASA, is associated with a significantly decreased risk of CM development. Clinical intervention studies are warranted to further investigate the potential role of ASA and other NSAIDs as chemopreventive agents for CM.JID JOURNAL CLUB ARTICLE: For questions, answers, and open discussion about this article, please go to http://www.nature.com/jid/journalclu

The association between atopic eczema and lymphopenia: results from a UK cohort study with replication in US survey data.

BACKGROUND: Lymphocyte skin homing in atopic eczema (AE) may induce lymphopenia. OBJECTIVE: To determine if AE is associated with lymphopenia. METHODS: We used UK primary care electronic health records (Clinical Practice Research Datalink GOLD) for a matched cohort study in adults (18yrs+) (1997-2015) with at least 1 recorded lymphocyte count. We matched people with AE to up to 5 people without. We used multivariable logistic regression to estimate the association between AE and lymphopenia (two low lymphocyte counts within 3 months) and linear mixed effects regression to estimate the association with absolute lymphocyte counts using all available counts. Cox proportional hazard models were used to investigate the effect of lymphopenia on common infections. We replicated the study using US survey data (National Health and Nutrition Examination Survey [NHANES]). RESULTS: Amongst 71,731 adults with AE and 126,349 adults without AE, we found an adjusted odds ratio (OR) for lymphopenia of 1.16 (95%CI: 1.09-1.23), the strength of association increased with increasing eczema severity. When comparing all recorded lymphocyte counts from adults with AE(n=1,497,306) to those of people without AE(n=4,035,870) we saw a lower mean lymphocyte (adjusted mean difference -0.047*109 /L (95%CI:- 0.051- -0.043)) in those with AE. The difference was larger for men, increasing age, increasing AE severity and was present among people with AE not treated with immunosuppressive drugs. In NHANES (n=22,624), the adjusted OR for lymphopenia in adults with AE was 1.30 (95% CI 0.80-2.11), and the adjusted mean lymphocyte count difference was -0.03*109 /L (95%CI -0.07-0.02). Despite having a lower lymphocyte count, adjusting for time with lymphopenia, did not alter risk estimates of infections. CONCLUSION: AE, including increasing AE severity, is associated with a decreasing lymphocyte count, regardless of immunosuppressive drug use.. Whether the decreasing lymphocyte count has wider health implications for people with severe eczema warrants further investigation

Practice Variation in Skin Cancer Treatment and Follow-Up Care: A Dutch Claims Database Analysis

Background: Quality indicators are used to benchmark and subsequently improve quality of healthcare. However, defining good quality indicators and applying them to high-volume care such as skin cancer is not always feasible. Objectives: To determine whether claims data could be used to benchmark high-volume skin cancer care and to assess clinical practice variation. Methods: All skin cancer care-related claims in dermatology in 2016 were extracted from a nationwide claims database (Vektis) in the Netherlands. Results: For over 220,000 patients, a skin cancer diagnosis-related group was reimbursed in 124 healthcare centres. Conventional excision reflected 75% of treatments for skin cancer but showed large variation between practices. Large practice variation was also found for 5-fluorouracil and imiquimod creams. The practice variation of Mohs micrographic surgery and photodynamic therapy was low under the 75th percentile, but outliers at the 100th percentile were detected, which indicates that few centres performed these therapies far more often than average. On average, patients received 1.8 follow-up visits in 2016. Conclusions: Claims data demonstrated large practice variation in treatments and follow-up visits of skin cancer and may be a valid and feasible data set to extract quality indicators. The next step is to investigate whether detected practice variation is unwarranted and if a reduction improves quality and efficiency of care

Dermatofibrosarcoma Protuberans Re-excision and Recurrence Rates in the Netherlands Between 1989 and 2016

Dermatofibrosarcoma protuberans is a rare soft tissue tumour with a very low (less than 0.5%) rate of metastasis. Rates of re-excision and recurrence were determined using data from the Netherlands Cancer Registry between 1989 and 2016. Of the 1,890 instances of dermatofibrosarcoma protuberans included, 87% were treated with excision, 4% with Mohs micrographic surgery, and 9% otherwise or unknown. Linked pathology data were retrieved for 1,677 patients. Half of all excisions (847/1,644) were incomplete and 29% (192/622) of all re-excisions were incomplete. The cumulative incidence of a recurrence was 7% (95% confidence interval (CI) 6–8) during a median followup of 11 years (interquartile range (IQR) 6–17). AfterMohs micrographic surgery (n = 34), there were no recurrencesduring a median follow-up of 4 years (IQR 3–6). Due to the high rate of incomplete excisions and recurrences after excision, this study supports the European guideline, which recommends treating dermatofibrosarcoma protuberans with Mohs micrographic surgery in order to decrease the rate of recurrence

Healthcare utilization and management of actinic keratosis in primary and secondary care: a complementary database analysis

Background The high prevalence of actinic keratosis (AK) requires the optimal use of healthcare resources. Objectives To gain insight in to the healthcare utilization of people with AK in a population-based cohort, and the management of AK in a primary and secondary care setting. Methods A retrospective cohort study using three complementary data sources was conducted to describe the use of care, diagnosis, treatment and follow-up of patients with AK in the Netherlands. Data sources consisted of a population-based cohort study (Rotterdam Study), routine general practitioner (GP) records (Integrated Primary Care Information) and nationwide claims data (DRG Information System). Results In the population-based cohort (Rotterdam Study), 69% (918 of 1322) of participants diagnosed with AK during a skin-screening visit had no previous AKrelated visit in their GP record. This proportion was 50% for participants with extensive AK (i.e. ≥ 10 AKs; n = 270). Cryotherapy was the most used AK treatment by both GPs (78%) and dermatologists (41–56%). Topical agents were the second most used treatment by dermatologists (13–21%) but were rarely applied in primary care (2%). During the first AK-related GP visit, 31% (171 of 554) were referred to a dermatologist, and the likelihood of being referred was comparable between low- and high-risk patients, which is inconsistent with the Dutch general practitioner guidelines for ‘suspicious skin lesions’ from 2017. Annually, 40 000 new claims representing 13% of all dermatology claims were labelled as cutaneous premalignancy. Extensive follow-up rates (56%) in secondary care were registered, while only 18% received a claim for a subsequent cutaneous malignancy in 5 years. Conclusions AK management seems to diverge from guidelines in both primary and secondary care. Underutilization of field treatments, inappropriate treatments and high referral rates without proper risk stratification in primary care, combined with extensive follow-up in secondary care result in the inefficient use of healthcare resources and overburdening in secondary care. Efforts directed to better risk differentiation and guideline adherence may prove useful in increasing the efficiency in AK management

Melanoma in older patients: declining gap in survival between younger and older patients with melanoma

Background: Older people have the highest incidence of melanoma and the population in most Western countries is ageing. We evaluated how the gap in incidence and survival between younger and older patients has developed during the past decades.Material and methods: All patients diagnosed with cutaneous melanoma between 1989 and 2015 (n = 84,827) were identified from the Netherlands Cancer Registry. Elderly were defined as aged ≥70 years. Differences in patient and tumor characteristics were described, age-specific incidence rates were calculated, and relative survival (RS) and multivariable analyses estimating the Relative Excess Rate of dying (RER) were conductedResults: In older men, the melanoma age-standardized incidence increased from 18 to 103/100,000 person-years (py) between 1989 and 2015 and in older women from 23 to 70/100,000 py. In younger men and women, it increased from 8 to 21 and from 13 to 28/100,000 py, respectively. Median Breslow thickness declined from 1.8 to 1.1 mm and from 1.6 to 1.1 mm in older men and women (2003 versus 2015), and from 1.1 to 0.9 mm and 0.9 to 0.8 mm in younger men and women. In older men, 5-year RS increased from 67% (95% CI: 63%-72%) in 1989-1997 to 85% (95% CI: 83%-87%) in 2007-2015 and in older women from 81% (95% CI: 78%-85%) to 89% (95% CI: 87%-91%). In younger men and women, RS increased from 82% (95% CI: 81%-83%) to 90% (95% CI: 90%-91%) and from 92% (95% CI: 92%-93%) to 96% (95% CI: 95%-96%). After case-mix correction , older men and women no longer showed an improved survival over time (RER 2010-2015 versus 2003-2009: 0.97; 95% CI: 0.81-1.16 and 0.95; 95% CI: 0.79-1.16). Whereas in younger men and women survival remained improved (RER 0.75; 95% CI: 0.67-0.83 and 0.77; 95%CI: 0.67-0.89).Conclusion: The gap in melanoma incidence between younger and older peopl

Effectiveness of dupilumab treatment in 95 patients with atopic dermatitis: daily practice data

Background: Dupilumab is the first biologic registered for the treatment of moderate-to-severe atopic dermatitis (AD), and efficacy was shown in phase III clinical trials (primary outcome at week 16 was reached in 38% of patients). Currently, there are limited daily practice data available for dupilumab, especially when it is combined with systemic immunosuppressants. Objectives: To evaluate dupilumab treatment in daily practice in patients with AD. Methods: In this observational cohort study, we prospectively included all adult patients with AD who had been treated with dupilumab in two university hospitals in the Netherlands. Concomitant systemic immunosuppressive treatment was monitored. Physician-reported outcome measures and patient-reported outcome measures (PROMs) after ≥ 12 we

Global epidemiology of actinic keratosis in the general population:a systematic review and meta-analysis

Background: Actinic keratosis (AK) is a common dermatological condition, and among the most common dermatological diagnoses in older populations. Although the prevalence of AK depends on demographic and environmental factors, little is known about the global context of AK. Objectives: To provide a comprehensive and updated analysis of the global prevalence rate and incidence of AK in the general population through a systematic review and meta-analysis, and - through subgroup analyses - to identify high-risk phenotypes, demographic and lifestyle risk factors and regional variations in disease prevalence. Methods: A systematic search of Embase, MEDLINE, Web of Science and Google Scholar was performed on 20 May 2022. Two reviewers independently screened and assessed the quality of each study using a validated critical appraisal checklist. Epidemiological measurements (e.g. prevalence) from individual studies performed in the general population were then pooled in a random-effects meta-analysis. Subgroup analyses (i.e. population age, geographical region, occupation, sex and study quality) were conducted. Results: Of the 65 articles that made it through the full-text screening, 60 reported a point prevalence. A meta-analysis of these articles yielded an overall point prevalence of 14% [95% confidence interval (CI) 14-15]. In further analyses, the calculated prevalence rate varied depending on subgroup. The pooled incidence rate from the seven eligible studies analysed was 1928 per 100 000 person-years (PY; 95% CI -439 to 4294). Conclusions: This comprehensive meta-analysis provides an updated global prevalence rate of AK of 14%, indicating a significant worldwide disease burden. The incidence rate of AK was found to be 1928 per 100 000 PY, emphasizing a growing public health concern. However, high heterogeneity among studies suggests that various factors influence the AK prevalence rate, necessitating further research to understand the observed differences.</p