Overview
Here we report results from a non-randomized, pragmatic, quasi-experimental, patient-engaged, comparative effectiveness research (CER) study [1] conducted by researchers at the University of New Mexico (UNM) comparing two distinct evidence-based models for culturally competent diabetes self-management and education programming. We compared outcomes at two sites in Albuquerque, New Mexico, serving a large Latinx patient population from low-income households. The overall study protocol is described in detail elsewhere [1]. Data collection involved interviews, focus groups, surveys, and testing of patient participants for A1c and depression. Survey responses, blood samples, and height/weight measurements were gathered at four time points (baseline, 3-months, 6-months, and 12-months). The UNM Human Research Review Committee/Institutional Review Board (HRRC/IRB # 16-303) approved all aspects of the research protocol.
Models for comparison
Local context for each model
The two models being compared were the Diabetes Self-Management Support Empowerment Model (DSMS) and [2] the Chronic Care Model (CCM) [3,4]. Each program serves a large population of Latinx patients from low-income households in Albuquerque, New Mexico, and employs a distinct evidence-based approach to create program cultural competence. Patient participants were recruited from both programs. One program, the Center for Diabetes Education at the University of New Mexico Hospital (CDE-UNMH), is based at a university hospital and uses the DSMS [2]. The other, One Hope, is based at a community clinic operated by a faith-based nonprofit and uses the CCM approach [3,4].
The Diabetes Self-Management Support Empowerment Model (DSMS)
The DSMS is a patient-centered, theoretically based educational framework that follows National Standards for Diabetes Self-Management Education [2], is certified by the American Diabetes Association [5], and is accredited by the American Association of Diabetes Educators (AADE) [5]. The DSMS combines a series of clinically informed group didactic sessions that use a patient self-determination approach to empower patients to take control of their own diabetes health with follow-up support to sustain self-management gains achieved during the sessions.
The Chronic Care Model (CCM)
The CCM is “a systematic approach to restructuring medical care to create partnerships between health systems and communities” [3,4] by addressing not only the medical but also the cultural and linguistic needs of patients through the inclusion of cultural competence in the delivery system design [3]. To create a holistic care regime, the CCM focuses on addressing social determinants of health by meeting patients' medical, cultural, and linguistic needs through integrating cultural norms and social relationships from the patient population into program design [6].
Measurements for Outcomes
Improved patient capacity for diabetes self-management
Capacity for diabetes self-management was measured using the Diabetes Knowledge Questionnaire (DKQ) and the Patient Activation Measure (PAM).
- Diabetes knowledge was measured using the DKQ summed score. We hypothesized that the Chronic Care Model (CCM) model would result in a larger increase in DKQ summed scores from baseline to 6 months as compared to the Diabetes Self-Management Support Empowerment Model DSMS. Previously published studies evaluating culturally competent diabetes management programs report meaningful changes in DKQ summed scores with Cohen’s f effect sizes of 0.03 to 0.16 in studies ranging in sample sizes per arm from 10 to 189 [7–10].
- Patient activation was measured using the PAM-10 raw score. We hypothesized that theCCM model would result in a larger increase in PAM-10 raw scores from baseline to 6 months as compared to the DSMS model. Previously published studies evaluating culturally competent diabetes management programs report changes in PAM-10 raw scores with meaningful Cohen’s f effect sizes of 0.01 to 0.16 in studies ranging in sample size per arm from 26 to 133 (per Shah, Co-I Burge, and colleagues) [11–15].
Improvement in A1c and PHQ-9
To measure physiological responses to out two intervention models, we used A1c and a depression scale score from the patient health questionnaire (PHQ-9) [16–18].
Participants
Dyadic enrollment design
We enrolled participants as dyads, where half were patients diagnosed with diabetes or pre-diabetes (“patient participants”) and half were individuals identified by the patient participant as someone in their lives who provides them with significant social support (“social support participants”). Including patient-social support dyads was a mechanism for incorporating the social dimension of patient’s lives in our research. Patient participants provided data related to their own health or experience. Social support participants primarily provided data on their perspective on their patient partner's health.
Patient participants (PPs)
Patient participants were individuals entering one of the two programs during the period of the study either because they were newly diagnosed with diabetes or pre/diabetes, or because they were having trouble managing their blood sugar levels. Patient participants were adults (≥18 years old), self-identified as Latinx(a), self-reported household income below 250% of the FPL, and were able to identify a social support who was willing to participate in the study.
Social support participants (SSPs)
The only requirements for social support participants were that they had to be adults (≥18 years old) and had to be willing to participate in the research. The social support did not have to be an actual “caregiver” to the patient, nor were they screened for ethnicity or income in order to participate.
Data collection
Each participant was enrolled in the study for 12 months. At baseline, all participants were asked demographic questions. At all four time points, we asked questions from validated survey instruments.
- Diabetes Knowledge Questionnaire (DKQ) [7–10].
- Patient Activation Measure 10 (PAM-10) [19–27].
- Patient Health Questionnaire (PHQ-9) [16–18].
- Consumer Assessment of Healthcare Providers and Systems Cultural Competence Set (CAHPS-CC).
At all four time points, we gathered blood samples from patient participants only. We also conducted interviews and focus groups with participants and providers.
Qualitative Analysis
We conducted a rigorous, disciplined, empirical analysis of qualitative data using Hammersley’scriteria for qualitative research based on plausibility, credibility, and relevance [28]. We conducted a theory-driven qualitative content analysis according to standards developed by Gläser and Laudel]. Three members of the research team (two bilingual) read through transcripts to identify conceptual categories and patterns related to specified domains of inquiry, and created a qualitative codebook. We explored interconnections between theme categories and developed a holistic interpretation of the data (“constant comparison”).
Quantitative Analysis
Sample size and Power Calculations
Our goal was to recruit N=240 patient-social support pairs (N=120 per site) in order to obtain complete data on N=96 pairs per site, assuming a 20% attrition rate. Comparing response changes on the DKQ, PAM-10, and PHQ-9 from baseline to 6 months between the CCM to the DSMS, the two-sided Type I error rate was adjusted for the number of comparisons made using a Bonferroni correction (α=0.025). The power analyses for detecting site differences among change scores were based on multiple linear regression models including demographic characteristics, participants’ perceived cultural competence of providers (CAHPS-CC), and social supports’ change scores on the DKQ, PAM-10, and PHQ-9 as covariates. We report Cohen’s f effect sizes based on the regression method, where Cohen’s standards for “small”, “medium”, and “large” effects are 0.02, 0.15, and 0.35, respectively [29,30].
The power for the primary endpoints with n=96 per site and α=0.025 for comparing the CCM to the DSMS was as follows
- Change in DKQ summed score: ΔCCM-DSCS = 2.2 (SD = 3.8), power = 96%, Cohen’s f effect size (ES)=0.09
- Change in PAM-10 raw score: ΔCCM-DSCS = 12.7 (SD = 24.8), power = 85%, Cohen’s f ES=0.07
The power for the secondary endpoints with n=96 per site and α=0.017 for comparing the CCM to the DSMS was as follows
- Change in A1c: ΔCCM-DSCS = -0.5 (SD=1.0), power = 84%, Cohen’s f ES=0.06.
- Change in depression scores (PHQ-9): ΔCCM-DSCS = -3 (SD=6), power = 84% Cohen’s f ES = 0.06.
Statistical analysis
Descriptive statistics were calculated to summarize PP characteristics. Medians and interquartile ranges (IQR) were calculated for continuous variables and were compared across sites by Kruskal-Wallis test. Frequencies and percentages were calculated for categorical variables and were compared with the chi-square test. Significant differences are noted.
Mean outcomes for Aims 1 and 2 over time and by program were analyzed using longitudinal linear mixed modeling [31,32] to account for the repeated measure effects, as well as to adjust for patient participant demographic characteristics. The interaction between time and program model was of primary interest to assess whether each outcome changed to different extents over time by program. Covariates that were excluded because of their strong relationship with site included primary language and type of insurance. The models used an unstructured covariance over time. The full models were fit and then reduced with backward model selection using conditional Akaike information criterion (cAIC)] Model fit assumptions on the residuals were equal variance and normality, which were both assessed visually. However, results were robust to violations of model distributional assumption. Analyses were performed in R 4.1.0. The restricted maximum-likelihood (REML) adjusted least-squares mean difference estimate of the outcome between programs from baseline to 6 months is reported along with its 95% confidence interval. The difference estimate from baseline to 12 months is also reported.
We conducted an analysisto assess patient participant capacity for diabetes self-management, our primary patient-reported outcome, by measuring diabetes knowledge using the DKQ and patient activation using the PAM-10. Descriptive statistics including means, standard deviations, medians, and quartiles were calculated for each outcome measure. Diabetes self-management program models were compared for the CCM vs the DSMS. P-values were compared to a Bonferroni-corrected α = 0.025 to account for multiple comparisons (two primary outcome measures). The primary outcome analyses were:
- Improvement in diabetes knowledge: Primary analysis used the DKQ summed score.
- Improvement in diabetes-related “patient activation”: Primary analysis used the PAM-10 raw score. We also converted raw scores to scaled scores per a proprietary algorithm [33] and then grouped them into patient activation levels which are displayed descriptively (frequencies and percentages) by diabetes self-management program model.
For our secondary outcome, successful patient participant management of their diabetes, we measured their A1c from blood samples drawn and PHQ-9 depression scores. The modeling used the longitudinal mixed model with the additional covariates of DKQ and PAM-10 for all three secondary outcomes and also PHQ-9 for A1c. Difference estimates are reported along with their 98.3% confidence intervals.
As part of our characterization of programmatic interface with patient participant culture and socio-economic circumstances(Aim #3), we summarized patient participant and social support participant scores on five of the eight subscales of the Consumer Assessment of Healthcare Providers and Systems Cultural Competence Set (CAHPS-CC) (Domains A. and B., F., G., and H.) aggregated over the three follow-up timepoints and treated as a fixed covariate to assess the overall program experience. Medians and quartiles of the subscales by diabetes self-management program model were reported. Social support participant scores were combined with the patient participant scores and used as covariates in the analysis for the quantitative primary and secondary outcome measures.