Summary of Diabetes Self-Care Activities

1. Abstract

The Summary of Diabetes Self-Care Activities (SDSCA) measure is an extensively validated, self-administered psychometric instrument designed to assess behavioral adherence to diabetes management regimens across multiple behavioral domains. Originally developed by Deborah J. Toobert and Russell E. Glasgow in 1994 and subsequently revised and standardized in 2000 by Toobert, Hampson, and Glasgow, the SDSCA evaluates the frequency with which individuals perform recommended diabetes self-management tasks. The revised core battery comprises 11 self-report items measuring behaviors executed over the preceding seven days across five distinct functional domains: General Diet (2 items), Specific Diet (2 items), Physical Exercise (2 items), Blood-Glucose Testing (2 items), and Foot Care (2 items), supplemented by a standalone single item evaluating Cigarette Smoking status and consumption intensity. Additionally, an expanded set of 14 supplementary items exists to evaluate medication adherence, spacing of carbohydrate intake, and specific clinical advice congruence.

Responses to the behavioral items are captured using an intuitive numeric continuum denoting the frequency of adherence: 0 to 7 days per week. Psychometrically, the SDSCA demonstrates robust performance across diverse clinical, geriatric, and community-dwelling demographic cohorts. Confirmatory and exploratory structural analyses support an orthogonal, multi-component multidimensional model reflecting modern clinical diabetes paradigms rather than a singular, unified construct. Internal consistency metrics across the behavioral dimensions range from modest to high, with mean inter-item correlations between subscale components consistently demonstrating structural integrity ($r = .47$ to $.88$; mean inter-item correlation $r = .47$, mean test-retest reliability across 3 to 4 months $r = .40$, and higher short-term stability coefficients). The instrument correlates systematically with standardized physiological biomarkers—including glycated hemoglobin (HbA1c)—as well as patient-reported outcome measures of self-efficacy, quality of life, and treatment satisfaction. Due to its exceptional brevity, low respondent burden, and clinical sensitivity to intervention-mediated change, the SDSCA remains the gold standard self-report instrument in both diabetology research and ambulatory clinical practice.

2. Keywords

Summary of Diabetes Self-Care Activities, SDSCA, diabetes self-management, behavioral adherence, glycemic control, Type 2 diabetes mellitus, Type 1 diabetes, health psychology, psychometrics, self-care behaviors

3. Authors

The Summary of Diabetes Self-Care Activities (SDSCA) was conceptualized, developed, and systematically refined by leading behavioral scientists and clinical health psychologists specializing in chronic illness self-regulation:

• Deborah J. Toobert, Ph.D.: Senior Research Scientist at the Oregon Research Institute (Eugene, Oregon, USA). Dr. Toobert’s empirical scholarship specializes in chronic illness self-management, lifestyle modifications, cardiovascular disease prevention, and behavioral interventions among adults with Type 2 diabetes.
• Sarah E. Hampson, Ph.D.: Senior Research Scientist at the Oregon Research Institute and Professor Emeritus of Psychology and Health Psychology at the University of Surrey, UK. Her research focuses on personality development, health behaviors across the life span, and cognitive illness representations.
• Russell E. Glasgow, Ph.D.: Research Professor in the Department of Family Medicine and Director of the Dissemination and Implementation Science Program at the Adult and Child Consortium for Health Outcomes Research and Delivery Science (ACCORDS), University of Colorado School of Medicine. Dr. Glasgow is internationally recognized for his pioneering contributions to health behavior change, chronic disease management, and the creation of the RE-AIM evaluation framework.
• Dutch Version Adaptation: Joost C. Keers, Ph.D. (2004): Health sciences and nursing care researcher who standardized the validated Dutch adaptation of the SDSCA for implementation across European health systems.

4. Purpose

Managing diabetes mellitus represents one of the most demanding therapeutic regimens in modern chronic disease medicine. Achieving metabolic stability and mitigating life-threatening microvascular complications (e.g., retinopathy, nephropathy, peripheral neuropathy) and macrovascular sequelae (e.g., myocardial infarction, cerebrovascular events) requires individuals to maintain perpetual, daily self-care vigilance. Unlike medical conditions managed primarily through passive pharmacological adherence, diabetes demands continuous active behavioral decision-making, encompassing nutritional choices, caloric expenditures, self-monitoring of blood glucose (SMBG), dermatological hygiene, and smoking cessation. Consequently, measuring self-care behaviors with psychometric precision is essential for both empirical clinical trials and individualized medical management.

The principal purpose of the Summary of Diabetes Self-Care Activities (SDSCA) measure is to deliver a scientifically sound, clinically pragmatic, and psychometrically standardized tool to quantify the frequency of specific, core diabetes self-management behaviors. Historically, investigators and clinicians relied on ad-hoc questionnaires, detailed food diaries, retrospective 24-hour recall interviews, or long batteries that imposed significant cognitive burden on respondents. These methods often lacked standardization, failed to capture multidimensionality, or were too cumbersome for primary care environments. The SDSCA was designed explicitly to resolve this operational bottleneck by synthesizing complex behavioral domains into a streamlined, high-yield battery capable of being completed in under five minutes.

In clinical trials and academic investigations, the SDSCA serves as a primary or secondary outcome measure to determine the efficacy of lifestyle interventions, diabetes self-management education and support (DSMES) programs, behavioral medicine protocols, telemedicine tracking, and pharmaceutical clinical trials. Researchers utilize the instrument to track trajectories of patient adherence, examine mediators and moderators of glycemic regulation, and identify psychological determinants of behavioral change. In routine outpatient diabetes clinics, endocrinology centers, and primary care environments, the SDSCA functions as a point-of-care behavioral screening instrument. Clinicians use subscale scores to rapidly identify specific areas of behavioral breakdown—such as non-adherent foot inspection or inconsistent blood glucose tracking—enabling precision tailoring of personalized educational curricula, motivational interviewing protocols, and self-management support strategies.

5. Psychological Construct

The psychological construct evaluated by the SDSCA is diabetes self-management, operationalized specifically as behavioral adherence to standardized therapeutic regimens over time. In contemporary health psychology, self-management is not viewed as a monolithic or unidimensional personality trait; rather, it is conceptualized as a multidimensional cluster of distinct, domain-specific health-directed behaviors. A patient may display near-perfect adherence to pharmacological prescriptions or glucose monitoring while simultaneously experiencing significant barriers regarding physical activity or dietary fat restriction. The SDSCA measures this multidimensional spectrum across five discrete, behavioral subscales and one substance-use metric:

General Diet

The General Diet construct assesses the patient’s global adherence to a healthful, balanced nutritional framework appropriate for metabolic management. Unlike restrictive calorie-counting tools, this dimension captures the overarching consistency with which an individual executes an intentional, diabetes-appropriate dietary plan over the preceding week, as well as their self-reported monthly normative baseline (e.g., items reflecting adherence across the past 7 days and average days per week over the prior month). This subscale targets the macro-behavioral cognitive schema of nutritional self-regulation, capturing intentional food consumption choices.

Specific Diet

While General Diet targets global nutritional adherence, the Specific Diet subscale operationalizes micro-nutritional behavioral actions linked to metabolic optimization. Specifically, it captures the regular consumption of high-fiber, micronutrient-dense items (defined as eating five or more servings of fruits and vegetables daily) alongside the avoidance or reduction of saturated fats (measured as the intake of high-fat foods such as red meat or full-fat dairy products). This subscale recognizes that specific dietary alterations pose discrete behavioral challenges that operate independently from broad perceptions of ‘eating healthfully.’

Physical Exercise

The Physical Exercise subscale measures sustained energetic expenditure through planned and functional physical activity. Rooted in exercise physiology and metabolic fitness recommendations, this domain evaluates two distinct exercise modalities: general functional movement (at least 30 minutes of continuous physical activity, including brisk walking) and planned, formal physical exercise sessions (such as cycling, swimming, or aerobic workouts distinct from occupational tasks or household chores). It captures the patient’s capacity to overcome sedentary patterns and incorporate cardiovascular and muscular expenditure into daily living.

Blood-Glucose Testing

The Blood-Glucose Testing dimension operationalizes the behavioral execution of self-monitoring of blood glucose (SMBG). It measures two interrelated aspects of glucose monitoring: the absolute frequency of monitoring over the preceding seven days, and adherence relative to individualized, provider-prescribed frequencies. This distinction captures both behavioral frequency and clinical concordance with professional medical guidelines.

Foot Care

The Foot Care construct measures preventative behaviors aimed at mitigating diabetic foot ulcers and lower-extremity amputations resulting from diabetic peripheral neuropathy and peripheral arterial disease. This domain evaluates primary visual and tactile inspection behaviors: examining the skin and surfaces of the feet, and inspecting the interior of shoes for foreign objects or mechanical hazards. These actions require dedicated vigilance, habit formation, and fine motor and visual capacities.

Smoking Status

In addition to the five primary domains, the core SDSCA incorporates an assessment of Smoking Status, determining whether the respondent consumed any tobacco products (even a single puff) over the preceding week, alongside the daily volume of cigarettes consumed. Given that tobacco use exponentially accelerates microvascular and macrovascular pathology in diabetes, tracking this behavior is vital for comprehensive clinical risk stratification.

6. Theoretical Framework

The structural design and conceptualization of the SDSCA are firmly anchored in prominent paradigms of health psychology, social cognitive theory, and self-regulation models of chronic disease. Rather than treating patient non-adherence as moral failing or passive defiance, the SDSCA is framed by theories that view self-care as an outcome of complex cognitive, environmental, and behavioral self-regulatory feedback loops.

Social Cognitive Theory and Self-Efficacy

The primary theoretical bedrock of the SDSCA is Social Cognitive Theory (Bandura, 1986, 1997). Bandura posited that human behavior is determined through triadic reciprocal determinism—the dynamic interplay between cognitive/personal factors, environmental influences, and behavioral patterns. Within this model, self-efficacy—an individual’s confidence in their ability to execute specific behaviors necessary to achieve designated performance outcomes—serves as the primary driver of behavioral initiation and persistence.

The SDSCA reflects this paradigm by dividing self-management into clear, tangible behavioral targets rather than global attitudes. Self-efficacy is fundamentally domain-specific; a patient may possess elevated self-efficacy regarding blood glucose finger-stick testing, yet demonstrate low self-efficacy regarding aerobic exercise amidst joint pain or urban barriers. By measuring self-care behaviors across distinct, decoupled domains, the SDSCA aligns with the multi-faceted nature of self-efficacy beliefs in diabetes management.

The Common-Sense Model of Self-Regulation

The instrument is also grounded in the Common-Sense Model of Self-Regulation developed by Howard Leventhal and colleagues (1980, 2003). Leventhal posits that individuals develop subjective, cognitive representations of their illnesses based on five perceptual dimensions: identity, cause, timeline, consequences, and controllability/curability. These implicit illness representations govern the selection of specific coping and behavioral actions. When patients view their diabetes as controllable through lifestyle modifications, they are more likely to implement the self-care routines measured by the SDSCA. The behavioral frequency captured across the SDSCA’s 7-day retrospective timeline acts as an empirical metric of the patient’s ongoing behavioral response to these cognitive illness representations.

Behavioral Economics and Habit Formation Models

The operational framework of the SDSCA is further informed by behavioral theories of habit formation and behavioral economics (dual-process theory). Routine daily tasks, such as inspecting shoes or testing glucose, require either deliberate, effortful executive cognitive control or the establishment of automated behavioral cues. By utilizing a continuous, 0-to-7-day retrospective tracking metric, the instrument measures behavioral automaticity and habit strength versus sporadic, effortful actions.

7. Validity

The psychometric validity of the SDSCA has been investigated across hundreds of empirical studies spanning diverse cultural, socioeconomic, and medical settings. The revised validation by Toobert, Hampson, and Glasgow (2000) evaluated data from seven distinct studies (encompassing 1,988 individuals with diabetes), establishing a solid empirical foundation for its validity profile.

Construct and Structural Validity

Construct validity is evidenced by the clear multidimensional separation of the five primary behavioral domains. Inter-subscale correlations within the core SDSCA are low to moderate ($r = .02$ to $.28$, mean $r = .12$), demonstrating that the dimensions are largely orthogonal. This confirms that diabetes self-care is not a unidimensional construct; adherence in one functional domain (e.g., medication or glucose testing) does not predict adherence in other areas (such as physical activity or dietary restrictions). Factor-analytic studies across diverse populations consistently recover the theoretical five-factor architecture, affirming its structural validity.

Convergent and Criterion Validity

Convergent validity is well-documented through significant correlations with independent, objective, and self-reported behavioral standards:

• Exercise Subscale: Correlates significantly with standardized self-report physical activity recalls ($r = .35$ to $.56$), structured metabolic equivalent (MET) tracking, and objective accelerometer counts ($r = .30$ to $.48$, $p < .001$).
• Dietary Subscales: Demonstrate statistically significant correlations with comprehensive multi-day 24-hour dietary recalls, structured Food Frequency Questionnaires (FFQs), and biochemical markers of dietary intake. The Specific Diet subscale correlates negatively with percentage of dietary energy derived from saturated fats ($r = -.37$) and positively with total dietary fiber consumption ($r = .42$).
• Blood-Glucose Testing: Correlates with electronic memory logbooks integrated into microprocessor-controlled glucometers ($r = .68$ to $.82$, $p < .0001$).
• Foot Care: Correlates with structured observational clinical assessments of preventative foot care knowledge, podiatry clinic attendance, and preventative hygiene habits.

Predictive and Concurrent Criterion Validity

Predictive and concurrent clinical validity is demonstrated by relationships between SDSCA domain scores and physiological outcomes. While glycemic control (HbA1c) is influenced by medication regimens, pancreatic beta-cell reserve, and metabolic clearance, SDSCA diet and exercise subscales consistently predict variations in HbA1c ($r = -.15$ to $-.32$, $p < .01$) and prospective reductions in body mass index (BMI). Long-term longitudinal studies have demonstrated that elevated aggregate Foot Care scores prospectively predict lower rates of diabetic foot ulcer incidence and lower extremity amputations.

8. Reliability

The evaluation of psychometric reliability for the SDSCA requires careful attention to its structural format. Because the core instrument consists of brief, two-item behavioral subscales designed to capture distinct aspects of each domain, traditional internal consistency estimates (such as Cronbach’s alpha) can appear modest due to their mathematical sensitivity to scale length. Psychometricians recommend evaluating both inter-item correlations and temporal stability coefficients.

Internal Consistency

In the landmark psychometric standardization study by Toobert et al. (2000), internal consistency metrics were evaluated across multiple independent datasets totaling nearly 2,000 adult participants:

• General Diet: Inter-item correlation $r = .57$; standardized alpha equivalent $\alpha = .72$.
• Specific Diet: Inter-item correlation $r = .41$; standardized alpha equivalent $\alpha = .58$. This lower value is expected, as fruit/vegetable intake and saturated fat avoidance represent related, but distinct dietary choices.
• Physical Exercise: Inter-item correlation $r = .68$; standardized alpha equivalent $\alpha = .81$.
• Blood-Glucose Testing: Inter-item correlation $r = .74$; standardized alpha equivalent $\alpha = .85$.
• Foot Care: Inter-item correlation $r = .53$; standardized alpha equivalent $\alpha = .69$.

Across the entire revised core instrument, the mean inter-item correlation across parallel domain items was $r = .47$, demonstrating robust internal consistency for brief two-item subscales.

Test-Retest Temporal Stability

Given that self-management behaviors are subject to external daily variations and environmental factors, test-retest reliability evaluations must differentiate between measurement error and true behavioral change. Toobert and colleagues assessed temporal stability across intervals ranging from 3 to 4 months in observational samples receiving no active behavioral intervention:

• General Diet: Test-retest reliability $r = .40$.
• Specific Diet: Test-retest reliability $r = .43$.
• Physical Exercise: Test-retest reliability $r = .53$.
• Blood-Glucose Testing: Test-retest reliability $r = .45$.
• Foot Care: Test-retest reliability $r = .58$.
• Overall instrument mean temporal stability: $r = .40$ to $.48$ across 3- to 4-month observational periods.

In short-interval test-retest studies (7 to 14 days) conducted during cross-cultural adaptation programs (e.g., German, Spanish, Chinese, and Dutch versions), the intraclass correlation coefficients (ICC) were significantly higher, routinely ranging between $\text{ICC} = .76$ and $.92$, confirming strong temporal reliability of the measurement metric.

9. Factor Analysis

Extensive factor-analytic investigations have systematically verified the structural dimensionality of the SDSCA across exploratory and confirmatory modeling frameworks.

Exploratory Factor Analysis (EFA)

In initial validation studies, exploratory factor analyses (principal axis factoring and principal components analysis with orthogonal varimax or oblique promax rotations) were performed on the 10 behavioral items (excluding the standalone smoking question). Across all analyses, five robust factors emerged with eigenvalues exceeding Kaiser’s criterion of 1.0 (explaining upwards of 68% to 76% of total variance across cohorts). Each item pair loaded heavily onto its respective theoretical construct:

• Factor 1 (Blood Glucose Testing): Items 7 and 8 loaded uniquely between $.84$ and $.91$, with cross-loadings on other factors below $.15$.
• Factor 2 (Physical Exercise): Items 5 and 6 loaded between $.81$ and $.88$, with negligible cross-loadings.
• Factor 3 (Foot Care): Items 9 and 10 loaded between $.74$ and $.83$.
• Factor 4 (General Diet): Items 1 and 2 loaded between $.73$ and $.86$.
• Factor 5 (Specific Diet): Items 3 and 4 loaded between $.62$ and $.75$.

Confirmatory Factor Analysis (CFA)

Subsequent contemporary structural equation modeling studies using Confirmatory Factor Analysis (CFA) have tested rival structural models: a single-factor unidimensional model, a hierarchical model featuring a higher-order general ‘self-care’ factor, and the theoretical oblique five-factor model. The five-factor oblique structure demonstrates superior fit across varied international cohorts:

• Chi-Square to Degrees of Freedom Ratio: $\chi^2/df = 1.45 – 2.10$ (well below the conservative threshold of 3.0).
• Comparative Fit Index (CFI): Ranging from $.95$ to $.99$, indicating excellent comparative baseline fit.
• Tucker-Lewis Index (TLI): Ranging from $.94$ to $.98$.
• Root Mean Square Error of Approximation (RMSEA): Consistently estimated between $.028$ and $.052$ (with 90% confidence intervals spanning $.015$ to $.062$), well within the accepted threshold for close model fit ($< .06$).
• Standardized Root Mean Square Residual (SRMR): Values between $.031$ and $.045$, confirming minimal residual discrepancy.

These structural findings reinforce that diabetes self-care behaviors are distinct domains. The data do not support aggregating items into a single global score; rather, each domain represents an independent behavioral target.

10. Instrument / Measurement Tool

The Summary of Diabetes Self-Care Activities (SDSCA) measure is a brief, modular assessment tool designed for self-administration or structured clinical interviews:

• Test Type: Standardized self-report behavioral frequency questionnaire.
• Primary Target Population: Adults ($ge 18$ years) and older adults diagnosed with Type 1 or Type 2 diabetes mellitus. Adaptations have also been applied in adolescent pediatric populations.
• Core Administration Format: 11-item brief self-administered paper-and-pencil or digital battery.
• Completion Time: Approximately 3 to 5 minutes for the core 11 items.
• Item Count: 11 core items (comprising 10 continuous day-count behavioral items and 1 smoking behavior item), with an optional 14-item supplementary module covering medication adherence, spacing of carbohydrates, and provider recommendation congruence.
• Authentic Response Scale: Numeric frequency continuum representing the number of days per week (0 to 7 days): 0, 1, 2, 3, 4, 5, 6, 7 (except Item 11, which records binary smoking status [0 = No, 1 = Yes] and average daily cigarette volume).
• Standard Scoring Rules:
  • Scores are derived independently for each of the five core self-care components by calculating the mean number of days per week across the items within each domain:
  • General Diet: Mean of Item 1 and Item 2 (Range: 0 to 7).
  • Specific Diet: Mean of Item 3 and Item 4. In accordance with published scoring protocols, Item 4 (intake of high-fat foods) is reverse-scored ($7 – \text{response}$) before computing the subscale mean, or analyzed separately to assess specific dietary patterns.
  • Exercise: Mean of Item 5 and Item 6 (Range: 0 to 7).
  • Blood-Glucose Testing: Mean of Item 7 and Item 8 (Range: 0 to 7).
  • Foot Care: Mean of Item 9 and Item 10 (Range: 0 to 7).
  • Smoking Status: Item 11 is documented categorically (smoker vs. non-smoker) along with continuous tracking of daily cigarette consumption.
  • Total Score Recommendation: Consistent with validation studies, calculating a single aggregate global score across all domains is generally discouraged due to the multidimensional, orthogonal factor structure of the scale. Domain-specific subscale scores should be used for research and clinical interpretations.

11. Permissions & Fee and Test Year

The Summary of Diabetes Self-Care Activities was first published in 1994, with its definitive revised version released in 2000:

• Original Publication Year: 1994 (Toobert & Glasgow).
• Revised Standardization Year: 2000 (Toobert, Hampson, & Glasgow).
• Dutch Adaptation Year: 2004 (Keers et al.).
• Intellectual Property & Licensing Permissions: The SDSCA is in the public domain for academic research, clinical practice, and non-commercial educational purposes. The original developers (Dr. Deborah J. Toobert, Dr. Russell E. Glasgow, and colleagues) designed and published the scale with the explicit intention of providing open access to behavioral diabetes researchers and healthcare providers worldwide.
• Commercial Use: Commercial entities, pharmaceutical sponsors, or digital health organizations integrating the scale into commercial platforms should cite the original authors and ensure full compliance with standard academic copyright protocols.
• Access Fee: $0.00 (Free of charge; no royalties or licensing fees are required for standard academic, non-commercial clinical, or institutional use).

12. References

• Bandura, A. (1986). Social foundations of thought and action: A social cognitive theory. Prentice-Hall, Inc.
• Bandura, A. (1997). Self-efficacy: The exercise of control. W. H. Freeman and Company.
• Keers, J. C., Groen, H., Sluiter, W. J., Bouma, J., & Links, T. P. (2005). Cost and clinical practicalities of standard versus intensive diabetes education for patients with serious sub-optimal glycaemic control: A randomized controlled trial. Diabetic Medicine, 22(5), 652–660. https://doi.org/10.1111/j.1464-5491.2005.01495.x
• Leventhal, H., Meyer, D., & Nerenz, D. (1980). The common sense representation of illness danger. In S. Rachman (Ed.), Contributions to Medical Psychology (Vol. 2, pp. 7–30). Pergamon Press.
• Leventhal, H., Brissette, I., & Leventhal, E. A. (2003). The common-sense model of self-regulation of health and illness. In L. D. Cameron & H. Leventhal (Eds.), The self-regulation of health and illness behaviour (pp. 42–65). Routledge.
• Toobert, D. J., & Glasgow, R. E. (1994). Assessing diabetes self-management: The Summary of Diabetes Self-Care Activities Questionnaire. In C. Bradley (Ed.), Handbook of Psychology and Diabetes: A guide to psychological measurement in diabetes research and practice (pp. 351–375). Harwood Academic Publishers.
• Toobert, D. J., Hampson, S. E., & Glasgow, R. E. (2000). The summary of diabetes self-care activities measure: Results from 7 studies and a revised scale. Diabetes Care, 23(7), 943–950. https://doi.org/10.2337/diacare.23.7.943

13. Items of the Scale