Confidence in Diabetes Self-Care Scale

Abstract

The Confidence in Diabetes Self-Care Scale (Dutch: Vertrouwen in diabetes zelfzorg [VDZ]; commonly abbreviated in international literature as CIDS) is an established psychometric instrument designed to assess diabetes-specific self-efficacy among individuals diagnosed with type 1 diabetes mellitus. Developed by Monique C. van der Ven, Katie Weinger, François Pouwer, Frank J. Snoek, and colleagues in 2003, the scale operationalizes Albert Bandura’s social cognitive construct of perceived self-efficacy within the demanding context of daily diabetes self-management. The CIDS consists of 20 items capturing an individual’s confidence in executing essential self-care behaviors across diverse, challenging clinical and lifestyle situations—including blood glucose testing, carbohydrate calculation, insulin dose adjustment, hypoglycemia management, dietary adherence under emotional stress, physical activity modulation, foot care, and regimen adherence during disrupted daily routines.

Each item is rated on a 5-point Likert scale ranging from 1 (“No, I am sure I cannot”) to 5 (“Yes, I am sure I can”), yielding a total score that ranges from 20 to 100, which can also be standardized to a 0–100 scale where higher scores indicate stronger diabetes self-efficacy. Psychometric evaluations across both Dutch and English-speaking adult cohorts have demonstrated robust structural, convergent, and discriminant validity. The CIDS exhibits strong internal consistency (Cronbach’s α typically ranging between .86 and .90) and satisfactory test-retest reliability. Factor-analytic investigations confirm a cohesive unidimensional construct representing generalized diabetes self-efficacy, alongside identifiable sub-facets related to glycemic management, lifestyle regulation, and coping with regimen distress. The CIDS is widely utilized in clinical diabetology, behavioral medicine, and psychological research to identify self-efficacy deficits, evaluate self-management education interventions, and predict glycemic control as measured by glycated hemoglobin (HbA1c).

Keywords

Confidence in Diabetes Self-Care, CIDS, Vertrouwen in diabetes zelfzorg, diabetes self-efficacy, type 1 diabetes mellitus, self-management, psychometrics, Social Cognitive Theory, glycemic control, behavioral medicine

Authors

The Confidence in Diabetes Self-Care (CIDS / VDZ) scale was developed through a bilateral collaboration between Dutch and American behavioral medicine researchers specializing in psycho-diabetology:

• N. Monique C. van der Ven, PhD – Department of Medical Psychology and the Institute for Research in Extramural Medicine (EMGO Institute), VU University Medical Center (VUmc), Amsterdam, The Netherlands.
• Katie Weinger, EdD, RN – Senior Investigator, Section on Behavioral and Mental Health, Joslin Diabetes Center; Associate Professor of Psychiatry, Harvard Medical School, Boston, Massachusetts, USA.
• J. Yi, MS – Joslin Diabetes Center, Harvard Medical School, Boston, Massachusetts, USA.
• François Pouwer, PhD – Department of Medical Psychology, VU University Medical Center, Amsterdam, The Netherlands; currently Professor of Medical Psychology, Department of Psychology, University of Southern Denmark, Odense, Denmark.
• Herman J. Adèr, PhD – Department of Clinical Epidemiology and Biostatistics, VU University Medical Center, Amsterdam, The Netherlands.
• Henk M. van der Ploeg, PhD – Department of Medical Psychology, EMGO Institute, VU University Medical Center, Amsterdam, The Netherlands.
• Frank J. Snoek, PhD – Professor of Medical Psychology, Head of the Department of Medical Psychology, Amsterdam University Medical Centers (location VUmc), Amsterdam, The Netherlands.

Purpose

The primary clinical and empirical purpose of the Confidence in Diabetes Self-Care Scale is to quantify an individual’s perceived capability to organize and execute the complex behavioral routines required to manage type 1 diabetes mellitus. Type 1 diabetes is a demanding chronic condition requiring relentless daily vigilance. Effective management hinges upon a multi-faceted behavioral regimen that includes frequent self-monitoring of blood glucose, precise estimation of dietary carbohydrates, calculation and administration of basal and bolus insulin, preemptive and reactive responses to exercise-induced glycemic shifts, prompt recognition and treatment of acute hypoglycemia, skin and foot inspections, and dynamic self-adjustment during illness, psychological distress, or environmental routine changes.

Crucially, medical outcomes in diabetes—most notably glycemic control, the prevention of acute diabetic ketoacidosis, severe hypoglycemia, and the mitigation of long-term microvascular and macrovascular complications—depend heavily on sustained self-care behaviors. However, clinical research has repeatedly demonstrated that knowledge of what behaviors to perform does not reliably predict actual self-care performance. Grounded in behavioral psychology, the CIDS was designed to capture the missing cognitive mediator: perceived task-specific self-efficacy. The scale explicitly measures the extent to which an individual believes they are capable of performing critical management actions, independent of whether they actually carry them out on a daily basis.

In clinical practice, the CIDS functions as a diagnostic and psychoeducational tool. Clinicians and diabetes educators use it to pinpoint specific domains where a patient feels inadequate or overwhelmed, distinguishing between knowledge gaps and confidence deficits. For instance, a patient may possess accurate theoretical knowledge regarding how to adjust insulin doses before aerobic exercise, yet lack the confidence to do so out of fear of exercise-induced nocturnal hypoglycemia. In empirical research, the CIDS serves as a standardized outcome measure for evaluating the efficacy of psychoeducational programs, cognitive-behavioral therapy (CBT), motivational interviewing interventions, and continuous glucose monitoring (CGM) or automated insulin delivery (AID) training paradigms. By assessing changes in self-efficacy, researchers can determine whether behavioral interventions achieve their target cognitive outcomes and examine how increases in confidence mediate downstream improvements in self-care frequency, psychological well-being, and glycemic markers.

Psychological Construct

The core construct measured by the CIDS is diabetes-specific self-efficacy. Rather than assessing generalized perceived self-efficacy or global optimism, the CIDS adheres to Bandura’s conceptual imperative that self-efficacy beliefs must be evaluated at a domain-specific and task-specific level to maintain predictive utility. In the CIDS, diabetes-specific self-efficacy reflects the subjective conviction that one can successfully orchestrate and execute specific disease-management behaviors under demanding, unpredictable, or emotionally taxing circumstances.

Core Dimensions of the Construct

While frequently analyzed as a unified composite score reflecting overall diabetes self-efficacy, the 20 items of the CIDS systematically encompass several vital sub-domains of diabetes self-regulation:

• Glycemic Monitoring and Data Interpretation: Confidence in checking blood glucose levels in response to physical cues (such as feeling high or low) and consistently maintaining records or interpreting digital memory logs (e.g., Items 1, 6). This dimension captures the cognitive willingness to engage with objective biological feedback, which is often avoided by patients suffering from diabetes-related shame or anxiety.
• Insulin Administration and Dynamic Dosing: The belief in one’s capacity to administer injections on schedule without omission, calculate bolus doses accurately based on glycemic readings, adjust insulin during illness, and modulate basal-bolus ratios in response to physical activity (e.g., Items 4, 5, 8, 13, 16). This represents a complex self-regulatory skill that requires quantitative reasoning and clinical risk management.
• Nutritional Calculation and Dietary Discipline: Confidence in accurately calculating mealtime carbohydrates, adhering to nutritional plans when dining outside the home, refusing non-recommended foods, and eating meals on time (e.g., Items 2, 3, 17, 18). Dietary management is frequently cited as the most socially and emotionally burdensome facet of diabetes care.
• Emergency Management and Safety Behaviors: Perceived agency in treating hypoglycemia immediately, carrying rescue carbohydrates at all times, and contacting health professionals during severe or unexplained hyperglycemia (e.g., Items 9, 10, 14). This sub-domain assesses resilience against the psychological panic and executive dysfunction often triggered by acute physiological distress.
• Affective Regulation and Coping Under Stress: Confidence in maintaining regimen adherence during periods of emotional upheaval, stress, depressive moods, lack of motivation, disrupted daily schedules, or frustration stemming from out-of-range blood glucose values (e.g., Items 11, 15, 19, 20). This dimension taps into self-regulatory stamina and executive control in the presence of competing negative affective states.
• Preventive Maintenance: The perceived capability to perform routine preventive behaviors, such as inspecting the feet for skin breakdown or ulcers, which are critical for preventing severe secondary diabetic complications (e.g., Item 12).

Theoretical Framework

The Confidence in Diabetes Self-Care Scale is anchored in Albert Bandura’s Social Cognitive Theory (Bandura, 1977, 1986, 1997). Within this framework, human psychological functioning is governed by triadic reciprocal causation, wherein cognitive and internal personal factors, behavioral patterns, and environmental influences operate as interacting determinants that influence each other bidirectionally.

A central tenet of Social Cognitive Theory is the distinction between outcome expectations and efficacy expectations. An outcome expectation is an individual’s estimate that a given behavior will lead to certain clinical or personal outcomes (for example, “Injecting the correct insulin dose will keep my HbA1c in target and prevent nephropathy”). In contrast, an efficacy expectation (self-efficacy) is the conviction that one can successfully execute the behavior required to produce the outcomes (“I am confident that I can calculate and inject the correct insulin dose even when I am at a crowded restaurant and feeling stressed”). Bandura demonstrated that knowledge of potential benefits is rarely sufficient to motivate action; individuals avoid tasks and situations they believe exceed their coping capabilities, while undertaking and persevering in activities they judge themselves capable of handling.

According to Bandura, perceived self-efficacy regulates human functioning across four major cognitive and emotional pathways:

1. Cognitive Processes: Individuals with high self-efficacy visualize success scenarios that provide positive guides and support for performance, whereas those with low self-efficacy visualize failure scenarios and obsess over potential pitfalls (such as severe hypoglycemia or social embarrassment).
2. Motivational Processes: Self-efficacy determines the goals people set for themselves, how much effort they expend, how long they persevere in the face of obstacles, and their resilience to setbacks. In diabetes, glycemic fluctuations occur despite meticulous care; individuals with high diabetes self-efficacy interpret glycemic variability as a problem to be analyzed and solved, whereas those with low self-efficacy interpret it as evidence of personal incompetence.
3. Affective Processes: Perceived coping efficacy dictates the degree of stress, diabetes distress, and depression experienced in the face of taxing demands. A strong sense of efficacy diminishes vulnerability to burnout and emotional paralysis.
4. Selection Processes: Confidence shapes the environments and activities an individual chooses to enter. High diabetes self-efficacy empowers patients to participate in sports, travel, and social dining without fear that their disease will spiral out of control.

The CIDS explicitly operationalizes efficacy expectations rather than outcome expectations or historical performance, focusing precisely on the subjective judgment: “Can I execute this specific self-care behavior when faced with this specific barrier?”

Validity

Validation studies conducted during the initial development and subsequent cross-cultural adaptations of the CIDS have established strong construct, convergent, discriminant, and criterion-related validity across adult populations with type 1 diabetes.

Construct and Convergent Validity

In the primary psychometric validation study conducted by van der Ven et al. (2003), the CIDS demonstrated significant positive correlations with validated measures of diabetes self-care behaviors, including the Summary of Diabetes Self-Care Activities (SDSCA) questionnaire and the Self-Care Inventory (SCI) (correlations ranging from $r = .35$ to $r = .55$, $p < .001$). Patients reporting higher scores on the CIDS engaged significantly more frequently in daily self-monitoring of blood glucose, adhered more closely to nutritional recommendations, and exhibited better medication compliance.

Convergent validity was further corroborated through moderate positive correlations with measures of generalized self-efficacy (such as the Schwarzer & Jerusalem General Self-Efficacy Scale; $r \approx .30\text{ to }.42$), confirming that while generalized mastery contributes to disease-specific confidence, the CIDS captures unique variance specific to the medical complexities of diabetes management.

Discriminant and Concurrent Validity

Discriminant validity has been consistently evidenced by inverse correlations with diabetes-specific psychological distress and general emotional distress. The CIDS correlates negatively with the Problem Areas in Diabetes (PAID) scale ($r = -.42\text{ to }-.58$, $p < .001$) and depressive symptoms as measured by the Center for Epidemiologic Studies Depression Scale (CES-D) ($r = -.28\text{ to }-.40$, $p < .01$). These findings demonstrate that patients who doubt their capacity to manage diabetes experience higher psychological distress and depressive affect, in full alignment with social cognitive models of chronic illness coping.

Criterion and Predictive Validity

The scale possesses demonstrated clinical criterion validity in relation to glycemic biomarkers. In cross-sectional and prospective studies, higher CIDS scores are inversely correlated with glycated hemoglobin levels (HbA1c) ($r = -.20\text{ to }-.35$, $p < .01$). Multiple linear regression models have verified that CIDS scores account for significant unique variance in HbA1c even after controlling for demographic variables (age, sex), disease duration, and insulin regimen modality. Longitudinal research indicates that improvements in CIDS scores following structured diabetes education programs (e.g., Blood Glucose Awareness Training [BGAT] or Dose Adjustment For Normal Eating [DAFNE]) prospectively predict subsequent decreases in HbA1c and lower rates of severe hypoglycemia over 6- to 12-month follow-ups.

Reliability

The psychometric evaluation of the Confidence in Diabetes Self-Care Scale demonstrates high reliability across both internal consistency and temporal stability paradigms.

Internal Consistency

In the initial psychometric validation study by van der Ven and colleagues (2003), evaluating both Dutch cohorts ($n = 286$) and American validation samples ($n = 227$), the overall scale yielded an internal consistency reliability coefficient (Cronbach’s alpha, $\alpha$) of .90 in the Dutch sample and .86 in the US sample. Subsequent independent clinical studies have routinely reported Cronbach’s alpha values ranging from .85 to .91, well above the standard threshold of .80 required for psychometric tools utilized in research and clinical evaluations. Corrected item-total correlations across the 20 items consistently surpass .35, indicating that each item contributes meaningfully to the overarching construct without redundancy.

Test-Retest Stability

Temporal stability was evaluated across a 2- to 4-week test-retest interval among clinically stable outpatients who experienced no changes in their diabetes therapeutic regimen. The intraclass correlation coefficient (ICC) for the total CIDS score was .85 ($p < .001$), and the Pearson test-retest correlation was $r = .84$, indicating substantial stability over time in the absence of targeted behavioral or educational interventions.

Standard Error of Measurement

The standard error of measurement (SEM) for the CIDS has been calculated at approximately 3.4 to 4.2 points on the 20–100 raw score scale. This small margin of error allows clinicians to calculate the Minimal Detectable Change (MDC) with 95% confidence (approximately 9.4 to 11.6 points), providing a reliable threshold for determining whether changes in a patient’s self-efficacy score after a psychoeducational intervention represent true behavioral-cognitive gains rather than measurement noise.

Factor Analysis

The structural dimensionality of the CIDS has been extensively evaluated using both Exploratory Factor Analysis (EFA) and Confirmatory Factor Analysis (CFA).

Exploratory Factor Analysis

During scale development, initial principal component and common factor analyses with oblique (Oblimin) and orthogonal (Varimax) rotations were performed on responses from adult patients with type 1 diabetes. Scree plot inspection, parallel analysis, and Kaiser’s eigenvalue criterion ($> 1.0$) revealed a strong, dominant primary factor accounting for the largest share of total variance (typically between 32% and 41% of common variance), supporting the calculation and interpretation of a single, omnibus CIDS composite score.

When multi-factor solutions were rotated, researchers identified three to four correlated sub-dimensions with distinct clinical coherence:

• Factor 1: Dynamic Insulin and Blood Glucose Regulation (Items 1, 4, 5, 6, 8, 9, 13, 16) – Focuses on insulin adjustments, testing under variable physiological conditions, and sickness protocols. Item loadings on this factor range from .48 to .78.
• Factor 2: Dietary Discipline and Social/Lifestyle Navigation (Items 2, 3, 7, 10, 15, 17, 18) – Covers meal planning, eating away from home, carbohydrate counting, exercise scheduling, and routine changes. Item loadings range from .42 to .72.
• Factor 3: Stress and Affective Self-Regulation (Items 11, 14, 19, 20) – Captures the capacity to maintain self-care during stress, low motivation, frustration with numbers, and seeking provider assistance. Item loadings range from .51 to .81.

Confirmatory Factor Analysis and Model Fit

Subsequent confirmatory factor analyses in independent validation cohorts tested both a strict unidimensional model and a hierarchical second-order model (where the specific sub-dimensions load onto a single higher-order Diabetes Self-Efficacy latent factor). The hierarchical model and the single-factor model with correlated error terms between closely linked items (e.g., items measuring meal planning under different conditions) demonstrated acceptable to good fit indices:

• Root Mean Square Error of Approximation (RMSEA): .052 to .068 (indicating acceptable fit below the .08 ceiling).
• Comparative Fit Index (CFI): .92 to .95 (satisfying conventional structural equation modeling adequacy criteria).
• Tucker-Lewis Index (TLI): .91 to .94.
• Standardized Root Mean Square Residual (SRMR): .048 to .059.

Because the primary higher-order factor accounts for substantial variance across all items, the scale developers and contemporary psychometric standards recommend utilizing the total 20-item composite score for overall clinical and research evaluations, while utilizing subscale patterns informally to guide personalized clinical consultations.

Instrument / Measurement Tool

• Tool Name: Confidence in Diabetes Self-Care Scale (Dutch: Vertrouwen in diabetes zelfzorg [VDZ]; Acronym: CIDS).
• Construct Assessed: Task-specific self-efficacy for type 1 diabetes self-management routines.
• Target Population: Adults and older adults (aged 18 years and older) diagnosed with Type 1 Diabetes Mellitus. Adaptations for adolescents with type 1 diabetes also exist in the broader literature.
• Administration Format: Paper-and-pencil self-report questionnaire, digital electronic survey, or clinical tablet administration.
• Item Count: 20 items.
• Response Format: 5-point Likert-type rating scale:
  • 1 = No, I am sure I cannot
  • 2 = Probably not
  • 3 = Maybe
  • 4 = Probably
  • 5 = Yes, I am sure I can
  • (Alternative standardized anchor format: 1 = Strongly disagree to 5 = Strongly agree)
• Scoring Rules:
  • All 20 items are formulated in a positive direction; there are no reverse-scored items.
  • Raw Total Score: Calculated by summing all individual item ratings. Scores range from 20 to 100. Higher scores reflect greater diabetes self-efficacy.
  • Transformed Percentage Score (0–100 Scale): Calculated as $\text{Standardized Score} = \left( \frac{\text{Raw Score} – 20}{80} \right) \times 100$. This linear transformation yields a percentage score where 0 represents absolute lack of confidence and 100 represents complete self-efficacy across all items.
  • Handling of Missing Data: If two or fewer items (≤ 10%) are missing, the mean of the completed items may be imputed for the missing items. If more than two items are missing, the total score should be treated as invalid.
• Completion Time: Approximately 5 to 10 minutes.

Permissions & Fee and Test Year

The Confidence in Diabetes Self-Care Scale was formally published in 2003 by Monique C. van der Ven, Katie Weinger, François Pouwer, Frank J. Snoek, and co-investigators. The instrument was developed within academic medical research institutions (VU University Medical Center, Amsterdam, and Joslin Diabetes Center / Harvard Medical School, Boston).

For non-commercial academic research, non-funded observational studies, and individual clinical patient care, the CIDS is generally accessible without royalty fees, provided full bibliographic citation and formal attribution are accorded to the original developers. For commercial use, inclusion in pharmaceutical trials, sponsored health technology platforms, or proprietary digital health applications, written permission and licensing agreements should be negotiated directly with the principal copyright holders or the corresponding academic departments (Department of Medical Psychology, Amsterdam University Medical Centers, Vrije Universiteit Amsterdam, The Netherlands, or Joslin Diabetes Center, Boston, MA).

References

• Bandura, A. (1977). Self-efficacy: Toward a unifying theory of behavioral change. Psychological Review, 84(2), 191–215. https://doi.org/10.1037/0033-295X.84.2.191
• Bandura, A. (1986). Social foundations of thought and action: A social cognitive theory. Prentice-Hall.
• Bandura, A. (1997). Self-efficacy: The exercise of control. W. H. Freeman.
• Polonsky, W. H., Anderson, B. J., Lohrer, P. A., Welch, G., Jacobson, A. M., Aponte, J. E., & Schwartz, C. E. (1995). Assessment of diabetes-related distress: The Problem Areas in Diabetes (PAID) scale. Diabetes Care, 18(6), 754–760. https://doi.org/10.2337/diacare.18.6.754
• Snoek, F. J., Pouwer, F., Welch, G. W., & Polonsky, W. H. (2000). Diabetes-related emotional distress in Dutch and U.S. diabetic patients: Cross-cultural validity of the Problem Areas in Diabetes Survey. Diabetes Care, 23(9), 1305–1309. https://doi.org/10.2337/diacare.23.9.1305
• 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
• van der Ven, N. C., Weinger, K., Yi, J., Pouwer, F., Adèr, H., van der Ploeg, H. M., & Snoek, F. J. (2003). The Confidence in Diabetes Self-Care Scale: Psychometric properties of a new tool for measuring diabetes self-efficacy in patients with type 1 diabetes. Diabetes Care, 26(3), 713–718. https://doi.org/10.2337/diacare.26.3.713
• Weinger, K., Butler, H. A., Welch, G. W., & Jacobson, A. M. (2005). Measuring diabetes self-care: A psychometric evaluation of the Self-Care Inventory-Revised with adults. Diabetes Care, 28(6), 1346–1352. https://doi.org/10.2337/diacare.28.6.1346

Items of the Scale