Causal Inference in Epidemiological Studies with Strong Confounding

One of the identifiabilty assumptions of causal effects defined by marginal structural model (MSM) parameters is the experimental treatment assignment (ETA) assumption. Practical violations of this assumption frequently occur in data analysis, when certain exposures are rarely observed within some strata of the population. The inverse probability of treatment weighted (IPTW) estimator is particularly sensitive to violations of this assumption, however, we demonstrate that this is a problem for all estimators of causal effects. This is due to the fact that the ETA assumption is about information (or lack thereof) in the data. A new class of causal models, causal models for realistic individualized exposure rules (CMRIER), introduced in van der Laan and Petersen (2007), is based on dynamic interventions. CMRIER generalize MSM, and their parameters remain fully identifiable from the observed data, even when the ETA assumption is violated, if the dynamic interventions are set to be realistic. Examples of such realistic interventions are provided. We argue that causal effects defined by CMRIER may be more appropriate in many situations, particularly those with policy considerations. Through simulation studies, we examine the performance of the IPTW estimator of the CMRIER parameters in contrast to that of the MSM parameters. We also apply the methodology to a real data analysis in air pollution epidemiology to illustrate the interpretation of the causal effects defined by CMRIER

Exploiting non‐systematic covariate monitoring to broaden the scope of evidence about the causal effects of adaptive treatment strategies

In studies based on electronic health records (EHR), the frequency of covariate monitoring can vary by covariate type, across patients, and over time, which can limit the generalizability of inferences about the effects of adaptive treatment strategies. In addition, monitoring is a health intervention in itself with costs and benefits, and stakeholders may be interested in the effect of monitoring when adopting adaptive treatment strategies. This paper demonstrates how to exploit non‐systematic covariate monitoring in EHR‐based studies to both improve the generalizability of causal inferences and to evaluate the health impact of monitoring when evaluating adaptive treatment strategies. Using a real world, EHR‐based, comparative effectiveness research (CER) study of patients with type II diabetes mellitus, we illustrate how the evaluation of joint dynamic treatment and static monitoring interventions can improve CER evidence and describe two alternate estimation approaches based on inverse probability weighting (IPW). First, we demonstrate the poor performance of the standard estimator of the effects of joint treatment‐monitoring interventions, due to a large decrease in data support and concerns over finite‐sample bias from near‐violations of the positivity assumption (PA) for the monitoring process. Second, we detail an alternate IPW estimator using a no direct effect (NDE) assumption. We demonstrate that this estimator can improve efficiency but at the potential cost of increase in bias from violations of the PA for the treatment process

The impact of telephonic wellness coaching on weight loss: A “Natural Experiments for Translation in Diabetes (NEXT‐D)” study

ObjectiveTo evaluate the impact of a population-based telephonic wellness coaching program on weight loss.MethodsIndividual-level segmented regression analysis of interrupted time series data comparing the BMI trajectories in the 12 months before versus the 12 months after initiating coaching among a cohort of Kaiser Permanente Northern California members (n = 954) participating in The Permanente Medical Group Wellness Coaching program in 2011. The control group was a 20:1 propensity-score matched control group (n = 19,080) matched with coaching participants based on baseline demographic and clinical characteristics.ResultsWellness coaching participants had a significant upward trend in BMI in the 12 months before their first wellness coaching session and a significant downward trend in BMI in the 12 months after their first session equivalent to a clinically significant reduction of greater than one unit of baseline BMI (P < 0.01 for both). The control group did not have statistically significant decreases in BMI during the post-period.ConclusionsWellness coaching has a positive impact on BMI reduction that is both statistically and clinically significant. Future research and quality improvement efforts should focus on disseminating wellness coaching for weight loss in patients with diabetes and those at risk for developing the disease

Wellness Coaching for People With Prediabetes: A Randomized Encouragement Trial to Evaluate Outreach Methods at Kaiser Permanente, Northern California, 2013

IntroductionHealth coaching can improve lifestyle behaviors known to prevent or manage chronic conditions. Little is known about effective ways to encourage health and wellness coaching among people who might benefit. The purpose of this randomized encouragement trial was to assess the relative success of 3 outreach methods (secured email message, telephone message, and mailed letter) on the use of wellness coaching by people with prediabetes.MethodsA total of 14,584 Kaiser Permanente Northern California (KPNC) patients with diagnosed prediabetes (fasting plasma glucose, 110-125mg/dL) were randomly assigned to be contacted via 1 of 4 intervention arms from January through May 2013. The uptake rate (making an appointment at the Wellness Coaching Center [WCC]) was assessed, and the association between uptake rate and patient characteristics was examined via multivariable logistic regression.ResultsThe overall uptake rate across intervention arms was 1.9%. Secured email message had the highest uptake rate (3.0%), followed by letters and telephone messages (P < .05 for all pairwise comparisons). No participants in the usual-care arm (ie, no outreach) made an appointment with the WCC. For each year of increased age, the estimated odds of the uptake increased by 1.02 (odds ratio [OR] = 1.02; 95% CI, 1.01-1.04). Women were nearly twice as likely to make an appointment at the WCC as men (OR = 1.87; 95% CI, 1.40-2.51).ConclusionOur results suggest that the WCC can recruit and encourage KPNC members with prediabetes to participate in the WCC. Future research should focus on increasing participation rates in health coaching among patients who may benefit

Patient Satisfaction and Perceived Success with a Telephonic Health Coaching Program: The Natural Experiments for Translation in Diabetes (NEXT-D) Study, Northern California, 2011

IntroductionHealth coaching can improve lifestyle behaviors known to prevent or manage chronic conditions such as diabetes. However, little is known about the patient experience with telephonic coaching programs in real-world care settings. We examined patient satisfaction, patient's perceived success in achieving program goals, and the patient-level correlates of these outcomes in a voluntary telephonic coaching program at a large integrated health care delivery system in northern California.MethodsKaiser Permanente Northern California patients who participated in a telephonic coaching program in 2011 were sent a cross-sectional survey about their satisfaction with health coaching and perceived success with program goals. We examined associations with patient characteristics.ResultsThe survey response rate was 34%; analyses were based on the 32% who completed the survey. Of those who had completed 2 or more sessions (n = 232 [52%]), most reported being satisfied (70%) or neutral (20%) with the program, and 71% would recommend health coaching. Healthy weight, healthful eating, and physical activity were the most common topics discussed (88%). Adjusting for demographic characteristics, 73% of those who had 2 or more sessions reported that health coaching helped achieve their weight-related goal. Outcomes were positively correlated with patient activation but not consistently correlated with patient demographic characteristics.ConclusionLevels of satisfaction and perceived success with telephonic health coaching provided by a health plan were high and positively correlated with the number of sessions completed and patient activation. Voluntary telephonic health coaching programs should promote retention and assess patients' activation levels

Telephone-Based Coaching

PurposeMany Americans continue to smoke, increasing their risk of disease and premature death. Both telephone-based counseling and in-person tobacco cessation classes may improve access for smokers seeking convenient support to quit. Little research has assessed whether such programs are effective in real-world clinical populations.DesignRetrospective cohort study comparing wellness coaching participants with two groups of controls.SettingKaiser Permanente Northern California, a large integrated health care delivery system.SubjectsTwo hundred forty-one patients who participated in telephonic tobacco cessation coaching from January 1, 2011, to March 31, 2012, and two control groups: propensity-score-matched controls, and controls who participated in a tobacco cessation class during the same period. Wellness coaching participants received an average of two motivational interviewing-based coaching sessions that engaged the patient, evoked their reason to consider quitting, and helped them establish a quit plan.MeasuresSelf-reported quitting of tobacco and fills of tobacco cessation medications within 12 months of follow-up.AnalysisLogistic regressions adjusting for age, gender, race/ethnicity, and primary language.ResultsAfter adjusting for confounders, tobacco quit rates were higher among coaching participants vs. matched controls (31% vs. 23%, p < .001) and comparable to those of class attendees (31% vs. 29%, p = .28). Coaching participants and class attendees filled tobacco-cessation prescriptions at a higher rate (47% for both) than matched controls (6%, p < .001).ConclusionTelephonic wellness coaching was as effective as in-person classes and was associated with higher rates of quitting compared to no treatment. The telephonic modality may increase convenience and scalability for health care systems looking to reduce tobacco use and improve health

Telephone-Based Coaching

PurposeMany Americans continue to smoke, increasing their risk of disease and premature death. Both telephone-based counseling and in-person tobacco cessation classes may improve access for smokers seeking convenient support to quit. Little research has assessed whether such programs are effective in real-world clinical populations.DesignRetrospective cohort study comparing wellness coaching participants with two groups of controls.SettingKaiser Permanente Northern California, a large integrated health care delivery system.SubjectsTwo hundred forty-one patients who participated in telephonic tobacco cessation coaching from January 1, 2011, to March 31, 2012, and two control groups: propensity-score-matched controls, and controls who participated in a tobacco cessation class during the same period. Wellness coaching participants received an average of two motivational interviewing-based coaching sessions that engaged the patient, evoked their reason to consider quitting, and helped them establish a quit plan.MeasuresSelf-reported quitting of tobacco and fills of tobacco cessation medications within 12 months of follow-up.AnalysisLogistic regressions adjusting for age, gender, race/ethnicity, and primary language.ResultsAfter adjusting for confounders, tobacco quit rates were higher among coaching participants vs. matched controls (31% vs. 23%, p < .001) and comparable to those of class attendees (31% vs. 29%, p = .28). Coaching participants and class attendees filled tobacco-cessation prescriptions at a higher rate (47% for both) than matched controls (6%, p < .001).ConclusionTelephonic wellness coaching was as effective as in-person classes and was associated with higher rates of quitting compared to no treatment. The telephonic modality may increase convenience and scalability for health care systems looking to reduce tobacco use and improve health