Discretized conformal prediction for efficient distribution-free inference

In regression problems where there is no known true underlying model, conformal prediction methods enable prediction intervals to be constructed without any assumptions on the distribution of the underlying data, except that the training and test data are assumed to be exchangeable. However, these methods bear a heavy computational cost-and, to be carried out exactly, the regression algorithm would need to be fitted infinitely many times. In practice, the conformal prediction method is run by simply considering only a finite grid of finely spaced values for the response variable. This paper develops discretized conformal prediction algorithms that are guaranteed to cover the target value with the desired probability, and that offer a tradeoff between computational cost and prediction accuracy

Chronic Obstructive Pulmonary Disease Self-Management in Three LMICs: A Pilot Randomized Trial

INTRODUCTION: Chronic obstructive pulmonary disease (COPD) disproportionately affects low- and middle-income countries (LMICs). Health systems are ill-prepared to manage the increase in COPD cases. METHODS: We carried out a pilot effectiveness-implementation randomized field trial of a community health worker (CHW)-supported, one-year self-management intervention in individuals with COPD grade B-D. The study took place in low-resource settings of Nepal, Peru, and Uganda. The primary outcome was the St. George's Respiratory Questionnaire (SGRQ) score at one year. We evaluated differences in moderate-to-severe exacerbations, all-cause hospitalizations and the EuroQol score (EQ5D-3L) at 12 months. RESULTS: We randomly assigned 239 participants (119 control, 120 intervention) with grade B-D COPD to a multi-component, CHW-supported intervention or standard of care and COPD education. 25 participants (21%) died or were lost to follow-up in the control arm compared to 11 (9%) in the intervention arm. At 12 months, there was no difference in mean total SGRQ scores between intervention and control arms (34.7 vs. 34.0 points; adjusted mean difference 1.0, 95% CI -4.2 to 6.1; p=0.71). The intervention arm had a higher proportion of hospitalizations (10% vs 5.2%; adjusted odds ratio 2.2, 95% CI 0.8-7.5; p=0.15) at 12 months compared to controls. CONCLUSION: A CHW-based intervention to support self-management of acute exacerbations of COPD in three resource-poor settings did not result in differences in SGRQ scores at one year. Fidelity was high, and intervention engagement was moderate. While results cannot differentiate between a failed intervention or implementation, it nonetheless suggests that we need to revisit our strategy. Clinical trial registration available at www. CLINICALTRIALS: gov, ID: NCT03359915

Stress Symptoms and Frequency of Sexual Intercourse Among Young Women

Introduction We have previously documented the relationships between stress and depression symptoms and adolescent women's nonuse and misuse of condoms and other contraceptive methods and on their unintended pregnancy rates. Aim Here, we examine relationships between mental health symptoms and another understudied adolescent reproductive health behavior—frequency of sexual intercourse. Main Outcome Measure Our outcome was weekly sexual intercourse activity. Methods We used panel data from a longitudinal, population‐based cohort study of 992 women ages 18–20. Weekly journals measured sociodemographic, relationship, reproductive, and mental health characteristics, sexual and contraceptive behaviors, and pregnancy history. We examined 27,130 surveys from 952 women during the first study year. Predictors of weekly sexual intercourse were moderate to severe stress (Perceived Stress Scale‐4) and depression (Center for Epidemiologic Studies Depression Scale‐5) symptoms measured at baseline. Multilevel, mixed‐effects logistic regression models estimated the relationships between stress and depression symptoms and the weekly odds of sexual intercourse while adjusting for covariate fixed effects and random woman effects. Results Nearly a quarter of the sample had moderate to severe stress (23%) and depression (24%) symptoms at baseline. Women reported sexual intercourse in 36% of weeks. Proportions of sexually active weeks were higher among women with stress (43%) and depression (40%) compared with those without symptoms (35% and 35%, respectively; P values < 0.001). Controlling for covariates, women with baseline stress symptoms had 1.6 times higher weekly odds of sexual intercourse compared with women without stress (adjusted odds ratio 1.6, confidence interval [1.1, 2.5]; P  = 0.04). Depression symptoms were not associated with sexual intercourse frequency in adjusted models. Conclusions Stress symptoms were positively associated with sexual intercourse frequency among these young women. Research and practice efforts are needed to identify effective sexual health promotion and risk‐reduction strategies, including contraceptive education and counseling, in the context of mental health symptoms and unintended pregnancy. Hall KS, Kusunoki Y, Gatny H, and Barber J. Stress symptoms and frequency of sexual intercourse among young women. J Sex Med 2014;11:1982–1990.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/107995/1/jsm12607.pd

Role of Young Women's Depression and Stress Symptoms in Their Weekly Use and Nonuse of Contraceptive Methods

Purpose: We prospectively examined the influence of young women's depression and psychological stress symptoms on their weekly contraceptive method use. Methods: We examined data from 689 women ages 18-20 years participating in a longitudinal cohort study. Women completed 8,877 weekly journals over the first year, which assessed reproductive, relationship, and health information. We focused on baseline depression (Center for Epidemiologic Studies-Depression Scale) and stress (Perceived Stress Scale) symptoms and weekly contraceptive method use. Analyses used multivariate random effects and multinomial logistic regression. Results: Approximately one quarter of women exhibited moderate/severe depression (27%) and stress (25%) symptoms at baseline. Contraception was not used in 10% of weekly journals, whereas coital and noncoital methods were used in 42% and 48% of weeks, respectively. In adjusted models, women with moderate/severe stress symptoms had more than twice the odds of contraception nonuse than women without stress (odds ratio [OR] 2.23, confidence interval [CI] 1.02-4.89, p = .04). Additionally, women with moderate/severe depression (RR .52, CI .40-.68, p < .001) and stress (relative risk [RR] .75, CI .58-.96, p = .02) symptoms had lower relative risks of using long-acting methods than oral contraceptives (OCs; reference category). Women with stress symptoms also had higher relative risks of using condoms (RR 1.17, CI 1.00-1.34, p = .02) and withdrawal (RR 1.29, CI 1.10-1.51, p = .001) than OCs. The relative risk of dual versus single method use was also lower for women with stress symptoms. Conclusion: Women's psychological symptoms predicted their weekly contraceptive nonuse and use of less effective methods. Further research can determine the influence of dynamic psychological symptoms on contraceptive choices and failures over time

Young women's consistency of contraceptive use - does depression or stress matter?

Background: We prospectively examined the influence of young women's depression and stress symptoms on their weekly consistency of contraceptive method use. Study Design: Women ages 18-20 years (n=689) participating in a longitudinal cohort study completed weekly journals assessing reproductive, relationship and health characteristics. We used data through 12 months of follow-up (n=8877 journals) to examine relationships between baseline depression (CES-D) and stress (PSS-10) symptoms and consistency of contraceptive methods use with sexual activity each week. We analyzed data with random effects multivarible logistic regression. Results: Consistent contraceptive use (72% of weeks) was 10-15 percentage points lower among women with moderate/severe baseline depression and stress symptoms than those without symptoms (p<.001). Controlling for covariates, women with depression and stress symptoms had 47% and 69% reduced odds of contraceptive consistency each week than those without symptoms, respectively (OR 0.53, CI 0.31-0.91 and OR 0.31, CI 0.18-0.52). Stress predicted inconsistent use of oral contraceptives (OR 0.27, CI 0.12-0.58), condoms (OR 0.40, CI 0.23-0.69) and withdrawal (OR 0.12, CI 0.03-0.50). Conclusion: Women with depression and stress symptoms appear to be at increased risk for user-related contraceptive failures, especially for the most commonly used methods. Implications: Our study has shown that young women with elevated depression and stress symptoms appear to be at risk for inconsistent contraceptive use patterns, especially for the most common methods that require greater user effort and diligence. Based upon these findings, clinicians should consider women's psychological and emotional status when helping patients with contraceptive decision-making and management. User-dependent contraceptive method efficacy is important to address in education and counseling sessions, and women with stress or depression may be ideal candidates for long-acting reversible methods, which offer highly effective options with less user-related burden. Ongoing research will provide a greater understanding of how young women's dynamic mental health symptoms impact family planning behaviors and outcomes over time