Practical methodology for missing data handling in interrupted time series analysis

Interrupted time series (ITS) is a quasi-experimental design for evaluating the effect of an intervention or treatment by comparing the outcome trajectory over time before and after initiation of the intervention. ITS became popular for evaluating interventions at the population level (e.g. policies); thus, the development of statistical methods was mainly orientated to modelling population-level data. This thesis aims to explore the issues that emerge when population-level ITS analyses are applied to incomplete individual-level data in health research, proposing alternative analysis methods. First, I performed a scoping review to demonstrate how the issues of missing data at the individual level have rarely been addressed in most recent ITS studies. Despite its limitations, complete case analysis is the most frequently used method for handling missing data. Individual-level data are usually transformed into population-level time-specific summaries before fitting ITS models. This method can lead to bias. Mixed effect models (MEM) can solve this, but my review demonstrates few studies have done so in the past. I then fitted MEM to study body weight gain induced by the initiation of antipsychotics using an ITS design on electronic health records. MEM allowed fully observed covariates to inform the implicit imputation of the outcome. ITS facilitated new clinical evidence: in the long-term, typical patients do not lose the weight they gained during the first six weeks of treatment. However, the MEM alone was not ideal for handling missing covariates (i.e. dosage). Thereafter, I used simulation studies to evaluate the performance of aggregate-level segmented regression (SR), MEM and multilevel multiple imputation (MI-JOMO) for handling data missing at random (MAR) in ITS analysis. I showed that the aggregate-level SR can over or underestimate the ITS effect. MEM is effective for handling outcomes MAR, but it should be combined with MI-JOMO when covariates are also MAR. Finally, I applied MEM with MI-JOMO to assess how dose and age modify the antipsychotic-induced weight gain. Interaction terms in MEM helped to evaluate differences in weight trajectories over time between groups by dose or age, using MI-JOMO for handling missing dose. Clinically, older people’s weight is less affected by the initiation of antipsychotic treatment than younger people’s

Cultural adaptation to Bolivian Quechua and psychometric analysis of the Patient Health Questionnaire PHQ-9

Objective: Cultural adaptation of the Patient Health Questionnaire-PHQ-9 to Bolivian Quechua and analysis of the internal structure validity, reliability, and measurement invariance by sociodemographic variables. Methods: The PHQ-9 was translated and back-translated (English-Quechua-English) to optimise translation. For the cultural adaptation, experts, and people from the target population (e.g., in focus groups) verified the suitability of the translated PHQ-9. For the psychometric analysis, we performed a Confirmatory Factor Analysis (CFA) to evaluate internal validity, calculated α and ω indices to assess reliability, and performed a Multiple Indicator, Multiple Cause (MIMIC) model for evaluating measurement invariance by sex, age, marital status, educational level and residence. We used standard goodness-of-fit indices to interpret both CFA results. Results: The experts and focus groups improved the translated PHQ-9, making it clear and culturally equivalent. For the psychometric analysis, we included data from 397 participants, from which 73.3% were female, 33.0% were 18–30 years old, 56.7% reported primary school studies, 63.2% were single, and 62.0% resided in urban areas. In the CFA, the single-factor model showed adequate fit (Comparative Fit Index = 0.983; Tucker-Lewis Index = 0.977; Standardized Root Mean Squared Residual = 0.046; Root Mean Squared Error of Approximation = 0.069), while the reliability was optimal (α = 0.869—0.877; ω = 0.874—0.885). The invariance was confirmed across all sociodemographic variables (Change in Comparative Fit Index (delta) or Root Mean Square Error of Approximation (delta) < 0.01). Conclusions: The PHQ-9 adapted to Bolivian Quechua offers a valid, reliable and invariant unidimensional measurement across groups by sex, age, marital status, educational level and residence.National Institute for Health and Care Researc

The short-form of the Cyberchondria Severity Scale (CSS-12): Adaptation and validation of the Spanish version in young Peruvian students

BACKGROUND: Cyberchondria is defined as the increase in health-related anxiety or anguish associated with excessive or repeated online searches for health-related information. Our objective was to cross-culturally adapt and validate the CSS-12 scale for Peruvian Spanish speakers, to determine whether the Bifactor model works as well in our population as in previous studies' and to explore whether the Bifactor-ESEM is a more suitable model. METHODS: We performed a cultural adaptation using the Delphi method and a validation study on medical students between 2018 and 2019. Reliability was evaluated by using Cronbach's alpha (α) and McDonald's omega (Ω) for internal consistency, and Pearson's r and intraclass correlation coefficient (ICC), for test-retest reliability. We evaluated construct validity by contrasting four measurement models for the CSS-12 and the convergent validity against health anxiety. RESULTS: The Spanish CSS-12 showed excellent reliability (α = .93; Ω = .93; ICC = .93; r = .96). The Bifactor ESEM model showed the best fit, supporting a unidimensional measure of the general cyberchondria. This measure was positively associated with health anxiety (r = .51). CONCLUSIONS: The Spanish CSS-12 provides a valid and reliable unidimensional measure of cyberchondria, which is distinguishable from the more general health anxiety. This can be applied to similar populations and future research. The Bifactor-ESEM model appears to offer a more accurate and realistic representation of the multifaceted nature of cyberchondria. We provide a free-to-use form of the Spanish CSS-12 as supplemental material

Current Practices in Missing Data Handling for Interrupted Time Series Studies Performed on Individual-Level Data: A Scoping Review in Health Research.

OBJECTIVE: Missing data can produce biased estimates in interrupted time series (ITS) analyses. We reviewed recent ITS investigations on health topics for determining 1) the data management strategies and statistical analysis performed, 2) how often missing data were considered and, if so, how they were evaluated, reported and handled. STUDY DESIGN AND SETTING: This was a scoping review following standard recommendations from the PRISMA Extension for Scoping Reviews. We included a random sample of all ITS studies that assessed any intervention relevant to health care (eg, policies or programmes) with individual-level data, published in 2019, with abstracts indexed on MEDLINE. RESULTS: From 732 studies identified, we finally reviewed 60. Reporting of missing data was rare. Data aggregation, statistical tools for modelling population-level data and complete case analyses were preferred, but these can lead to bias when data are missing at random. Seasonality and other time-dependent confounders were rarely accounted for and, when they were, missing data implications were typically ignored. Very few studies reflected on the consequences of missing data. CONCLUSION: Handling and reporting of missing data in recent ITS studies performed for health research have many shortcomings compared with best practice

Mental health among the sugarcane industry farmers and non-farmers in Peru: a cross-sectional study on occupational health.

OBJECTIVE: Describe the occupational characteristics of farmer and non-farmer workers and investigate critical occupational risk factors for mental disorders in sugarcane farmers in Peru. METHOD: We conducted a cross-sectional study with occupational health and safety focus among farmers and non-farmers. Mental disorder symptoms were evaluated through the local validated version of the 12-Item General Health Questionnaire (GHQ-12). We explored the association between mental disorder symptoms, work conditions and known occupational risk factors (weekly working hours, pesticide exposures, heat stress and heavy workload). Negative binomial regression models were fitted, and 95% CIs were calculated. RESULTS: We assessed 281 workers between December 2019 and February 2020. One hundred and six (37.7%) respondents identified themselves as farmworkers. The mean GHQ-12 scores for farmers and non-farmers were 3.1 and 1.3, respectively. In the fully adjusted multivariable model, mental disorder symptom counts among farmers were more than twice as high as those of non-farmers (β: 2.11; 95% CI: 1.48 to 3.01). The heavy workload increased the mean number of mental disorder symptoms by 68% (95% CI: 21% to 133%), and each additional working hour per day increased the mean number of mental disorder symptoms by 13% (95% CI: 1% to 25%). CONCLUSION: Farmers have higher mental disorder symptoms than non-farmers. A heavy workload and more working hours per day are independently associated with more mental disorder symptoms. Our findings highlight the importance of including mental health within occupational programmes and early interventions tailored to sugarcane industrial mill workers in the Latin American context

Tobacco consumption and positive mental health: an epidemiological study from a positive psychology perspective.

BACKGROUND: Positive mental health (PMH) is much more than the absence of mental illnesses. For example, PMH explains that to be happy or resilient can drive us to live a full life, giving us a perception of well-being and robustness against everyday problems. Moreover, PMH can help people to avoid risky behaviours like tobacco consumption (TC). Our hypothesis was that PMH is negatively associated with TC, and this association differs across rural, urban and migrant populations. METHODS: A cross-sectional study was conducted using the PERU MIGRANT Study's dataset, including rural population from the Peruvian highlands (n = 201), urban population from the capital city Lima (n = 199) and migrants who were born in highlands but had to migrated because of terrorism (n = 589). We used an adapted version of the 12-item Global Health Questionnaire to measure PMH. The outcome was TC, measured as lifetime and recent TC. Log-Poisson robust regression, performed with a Maximum Likelihood method, was used to estimate crude prevalence ratios (PR) and 95 % confidence intervals (95%CI), adjusted by sex, age, family income and education which were the confounders. The modelling procedure included the use of LR Test, Akaike information criteria (AIC) and Bayesian information criteria (BIC). RESULTS: Cumulative occurrence of tobacco use (lifetime TC) was 61.7 % in the rural group, 78 % in the urban group and 76.2 % in rural-to-urban migrants. Recent TC was 35.3 % in the rural group, 30.7 % in the urban group and 20.5 % in rural-to-urban migrants. After adjusting for confounders, there was evidence of a negative association between PMH and lifetime TC in the rural group (PR = 0.93; 95%CI: 0.87-0.99), and a positive association between PMH and recent TC in migrants (PR = 1.1; 95%CI: 1.0-1.3). CONCLUSIONS: PMH was negatively associated with TC in rural participants only. Urbans exhibited just a similar trend, while migrants exhibited the opposite one. This evidence represents the first step in the route of knowing the potential of PMH for fighting against TC. For rural populations, this study supplies new information that could support decisions about prevention programmes and psychotherapy for smoking cessation. However, more research in the topic is needed

Adaptación cultural al Quechua y análisis psicométrico del Patient Health Questionnaire PHQ-9 en población peruana

Objective. To translate and culturally adapt the Patient Health Questionnaire (PHQ-9) to three varieties of Quechua and analyse their validity, reliability, and measurement invariance. Materials and methods. 1) Cultural adaptation phase: the PHQ-9 was translated from English into three variants of Quechua (Central, Chanca, Cuzco-Collao) and translated again into English. Then, experts and focus groups allowed the translations to be culturally adapted. 2) Psychometric phase: the unidimensionality of the adapted PHQ-9 was evaluated by using Confirmatory Factor Analysis (CFA), reliability was evaluated by internal consistency (Alpha and Omega), and measurement invariance according to Quechua varieties and sociodemographic variables was evaluated by using CFA, multigroups and MIMIC models (Multiple Indicator Multiple Cause). Results. Each of the adaptations of the PHQ-9 to the three Quechua varieties reported clear and culturally equivalent items. Subsequently, data from 970 Quechua- speaking adult men and women were analyzed. The general one-dimensional model reported an adequate fit (Comparative fit index = 0.990, Tucker-Lewis index = 0.987, Standardized root mean squared residual= 0.048, Root mean squared error of approximation= 0.071); each of the Quechua varieties also showed an adequate fit. Reliability was high for all varieties (α = 0.865 - 0.915; ω = 0.833 - 0.881). The results of the multigroup CFA and MIMIC models confirmed measurement invariance according to Quechua variant, sex, residence, age, marital status and educational level. Conclusions. The PHQ-9 adaptations to Central Quechua, Chanca and Cuzco-Collao offer a valid, reliable and invariant measurement, confirming that comparisons can be made between the evaluated groups. Its use will benefit mental health research and care for Quechua-speaking populations

Effects of long-term antipsychotics treatment on body weight: A population-based cohort study.

BACKGROUND: Antipsychotics are often prescribed for long-term periods, however, most evidence of their impact on body weight comes from short-term clinical trials. Particularly, impact associated with dosage has been barely studied. AIMS: The aim of this study was to describe the short- and long-term change in body weight of people initiated on high or low doses of the three most commonly prescribed second-generation antipsychotics. METHODS: Retrospective cohorts of individuals with a diagnosed psychotic disorder observed from 2005 to 2015 in the UK primary care. The exposure was the first prescription of olanzapine, quetiapine or risperidone. The main outcome was change in body weight four years before and four years after initiation of antipsychotic treatment, stratified on sex and 'low' or 'high' dose. RESULTS: In total, 22,306 women and 16,559 men were observed. Olanzapine treatment was associated with the highest change in weight, with higher doses resulting in more weight gain. After 4 years, given a high dose of olanzapine (> 5 mg), women gained on average +6.1 kg; whereas given a low dose (⩽ 5 mg), they gained +4.4 kg. During the first six weeks of olanzapine treatment, they gained on average +3.2 kg on high dose and +1.9 kg on low dose. The trends were similar for men. Individuals prescribed risperidone and quetiapine experienced less weight gain in both the short- and long-term. CONCLUSIONS: Olanzapine treatment was associated with the highest increase in weight. Higher doses were associated with more weight gain. Doctors should prescribe the lowest effective dose to balance mental-health benefits, weight gain and other adverse effects

Development of a Mobile Health Application Based on a Mixed Prenatal Care in the Context of COVID-19 Pandemic

OBJECTIVE: We describe the development and structure of a novel mobile application in a mixed model of prenatal care, in the context of the COVID-19 pandemic. Furthermore, we assess the acceptability of this mobile app in a cohort of patients. METHODS: First, we introduced a mixed model of prenatal care; second, we developed a comprehensive, computer-based clinical record to support our system. Lastly, we built a novel mobile app as a tool for prenatal care. We used Flutter Software version 2.2 to build the app for Android and iOS smartphones. A cross-sectional study was carried out to assess the acceptability of the app. RESULTS: First, we introduced a mixed model of prenatal care; second, we developed a comprehensive, computer-based clinical record to support our system. Lastly, we built a novel mobile app as a tool for prenatal care. We used Flutter Software version 2.2 to build the app for Android and iOS smartphones. A cross-sectional study was carried out to assess the acceptability of the app. CONCLUSION: This novel mobile app was developed as a tool among pregnant patients to increase the information available about their pregnancies in the provision of a mixed model of prenatal care in the context of the COVID-19 pandemic. It was fully customized to the needs of our users following the local protocols. The introduction of this novel mobile app was highly accepted by the patients

Adaptation of the Bergen Social Media Addiction Scale (BSMAS) in Spanish

The impact of social networks on people's daily lives is worrisome, particularly in adolescents and young people, who seem to exceed the limits of normal use. Constant excessive use can lead to pathological behaviors linked to social media addiction (SMA). Our objectives were to 1) adapt the Bergen Social Media Addiction Scale (BSMAS) to Spanish and 2) evaluate its psychometric properties in a young population. The BSMAS was adapted to Spanish, involving experts on social media addiction and people from the target population during the adaptation process. For the psychometric evaluation, 650 Peruvian college students responded to the Spanish version (53.5 % women aged 18 to 40, M = 21.5 SD = 2.7). The one-dimensional measurement model proposed for the original BSMAS was confirmed for our version (X2(9) = 23.9315, CFI = 0.994, TLI = 0.990, SRMR = 0.032, RMSEA = 0.061). The reliability was good (α = 0.863; 95 % CI: 0.848–0.870; ω = 0.864; 95 % CI: 0.846–0.844), and the measurement invariance was confirmed for sex and age by fitting models. The concurrent validity with external social media addiction and mental health indicators was also confirmed. This study provides new and relevant information on the BSMAS validity and allows its application to Spanish-speaker college students from Peru and similar countries.info:eu-repo/semantics/publishedVersio