Stages and Processes of Change for Weight Loss in Acute Stroke or TIA Patients Living with Obesity

BACKGROUND

Obesity is associated with an increased prevalence of vascular risk factors and incidence of stroke. As such weight loss is recommended for patients living with obesity in the secondary prevention of stroke. Few studies, however, have examined the stages and processes of change for weight loss in stroke patients living with obesity.

OBJECTIVE

To evaluate the stages and processes of change for weight loss in patients living with obesity who have had a recent stroke or TIA.

METHODS

Using a validated questionnaire, we assessed each patient's stage of behavioral change according to the Transtheoretical Model (precontemplation, contemplation, preparation, action and maintenance). We also examined four processes of behavioral change, which quantify activities and experiences that patients undergo on the way to behavioral change: emotional re-evaluation (EMR), weight management action (WMA), weight consequence evaluation (WCE), and supporting relationships (SR). Processes scores were compared between patients in the action and maintenance stages and those in the precontemplation, contemplation and preparation stages.

RESULTS

Out of 49 patients who provided informed consent, 44 met the inclusion/exclusion criteria. Of these 44 patients, 6 (14%) were in the precontemplation stage of change, 7 (16%) were in contemplation, 2 (5%) were in preparation, 13 (30%) were in action, and 16 (36%) were in maintenance. Those in the action and maintenance stages accounted for the majority of participants (n=29, 66%). Patients in the action and maintenance stages (N=29) had higher EMR scores (mean 79, SD 13 vs mean 68, SD 19, t=2.0, p=0.03) and WMA scores (mean 69, SD 13 vs mean 59, SD 19, t=2.0, p=0.03) as compared to those in the precontemplation, contemplation and preparation stages (N=15).

CONCLUSIONS

Our results suggest that without counseling or specific intervention, approximately two-thirds of stroke/TIA patients living with obesity are in the action or maintenance stage of behavior change with respect to weight loss and therefore more likely to succeed in intensive lifestyle-based interventions targeted towards weight loss. Patients who score higher in EMR and WMA are more likely to be in the action or maintenance stage of change.

Pioglitazone Therapy in Patients With Stroke and Prediabetes: A Post Hoc Analysis of the IRIS Randomized Clinical Trial

Importance

In the Insulin Resistance Intervention After Stroke (IRIS) randomized clinical trial, pioglitazone, an insulin-sensitizing agent, reduced the risk for recurrent stroke or myocardial infarction (MI) among patients with insulin resistance. However, insulin resistance is not commonly measured in clinical practice.

Objective

To analyze the effects of pioglitazone in patients with good adherence as well as intention-to-treat effects of pioglitazone in patients with prediabetes in the IRIS trial.

Design, Setting, and Participants

The IRIS trial was a randomized multicenter clinical trial in patients with prior stroke or transient ischemic attack as well as insulin resistance but not diabetes. Patients were enrolled from February 2005 to January 2013, and the median follow-up was 4.8 years. The post hoc analyses reported here were performed from June to September 2018. Per American Diabetes Association criteria, prediabetes was defined as having a hemoglobin A1c level of 5.7% to 6.4% or fasting plasma glucose level of 100 mg/dL to 125 mg/dL (to convert to mmol/L, multiply by 0.0555). Good adherence was defined as taking 80% or more of the protocol dose. Fasting glucose and hemoglobin A1c, used to define prediabetes, and adherence of 80% or higher, stipulated in the protocol as defining good adherence, were prespecified subgroups in the analysis plan.

Interventions

Participants were randomized to 15 mg of pioglitazone, with dose titrated to target of 45 mg daily, or matching placebo.

Main Outcomes and Measures

The primary outcome was recurrent stroke or MI. Secondary outcomes included stroke, acute coronary syndrome, stroke/MI/hospitalization for heart failure, and progression to diabetes.

Results

Among 3876 participants analyzed in the IRIS trial, 2885 were included in this analysis (1456 in the pioglitazone cohort and 1429 in the placebo cohort). The mean (SD) age of patients was 64 (11) years, and 974 (66.9%) and 908 (63.5%) of patients were men in the pioglitazone and placebo cohort, respectively. In the prediabetic population with good adherence (644 of 1456 individuals [44.2%] in the pioglitazone group and 810 of 1429 [56.7%] in the placebo group), the hazard ratios (95% CI) were 0.57 (0.39-0.84) for stroke/MI, 0.64 (0.42-0.99) for stroke, 0.47 (0.26-0.85) for acute coronary syndrome, 0.61 (0.42-0.88) for stroke/MI/hospitalization for heart failure, and 0.18 (0.10-0.33) for progression to diabetes. There was a nonsignificant reduction in overall mortality, cancer, and hospitalization, a slight increase in serious bone fractures, and an increase in weight gain and edema. Intention-to-treat results also showed significant reduction of events but to a lesser degree. Hazard ratios (95% CI) were 0.70 (0.56-0.88) for stroke/MI, 0.72 (0.56-0.92) for stroke, 0.72 (0.52-1.00) for acute coronary syndrome, 0.78 (0.63-0.96), for stroke/MI/hospitalization for heart failure, and 0.46 (0.35 to 0.61) for progression to diabetes.

Conclusions and Relevance

Pioglitazone may be effective for secondary prevention in patients with stroke/transient ischemic attack and with prediabetes, particularly in those with good adherence.

Trial Registration

ClinicalTrials.gov identifier: NCT00091949.

Abstract TMP92: Pioglitazone for Secondary Stroke Prevention in Pre-diabetes: Implications for Real-world Practice

Pioglitazone reduces insulin resistance and cardiovascular risk among patients with type 2 diabetes. The Insulin Resistance Intervention after Stroke (IRIS) trial randomized 3876 non-diabetic participants with recent stroke/TIA and insulin resistance based on the Homeostasis Model of Insulin Resistance (HOMA-IR) score to pioglitazone (PIO) vs. placebo (PLA). Over 4.8 years, the relative risk reduction (RRR) with PIO was 27% for stroke/myocardial infarction, 25% for stroke, 29% for acute coronary syndrome (ACS), and 52% for new-onset diabetes. PIO could therefore be considered a new therapy for secondary stroke prevention before diabetes onset. However, it is not in widespread use, not only because of increased fracture risk, but perhaps also because HOMA-IR is not commonly assessed in clinical practice. In contrast, the presence of prediabetes is often identified in this population. We therefore analyzed the intention-to-treat (ITT) and the on-treatment effect of PIO (defined as adherence of > 80%) in IRIS participants with prediabetes by the American Diabetes Association criteria: HbA1C 5.7%-6.4%, or fasting glucose 100-125 mg/dL (n=2885; PIO 1456, PLA 1429). By ITT, for pioglitazone the hazard ratio and 95% confidence interval in Cox regression for stroke/MI was 0.70 (0.56-0.88, p=0.002), for stroke 0.72 (0.56-0.93, p=0.013), for ACS 0.72 (0.52-1.00, p = 0.052), for stroke/MI/hospitalized heart failure (HHF) 0.78 (0.63-0.96, p=0.02), and for new-onset diabetes HR 0.46 (0.34-0.61, p <0.0001). Among participants with good adherence, pioglitazone participants (n=644) were more likely to be men (76.2% vs 70.6%, p=0.02) and more likely to be smokers (15.9% vs. 11.7%, p=0.02) compared to PLA participants (n=810). In this subgroup, the HR for stroke/MI was 0.57 (0.39-0.84, p=0.004), for stroke 0.64 (0.42-0.99, p=0.04), for ACS 0.47 (0.26-0.85, p=0.01), for stroke/MI/HHF 0.61 (0.42-0.88, p=0.008), and for new-onset diabetes HR 0.18 (0.10-0.33, p<0.0001)

Conclusion: Pioglitazone should be considered efficacious for secondary prevention in stroke/TIA participants with prediabetes, simply assessed by fasting plasma glucose or A1C.