Figure. The Person-Centered Dermatology Self-Care Index 2.
Cowdell F, Ersser SJ, Gradwell C, Thomas PW. The Person-Centred Dermatology Self-Care Index: a tool to measure education and support needs of patients with long-term skin conditions. Arch Dermatol. doi:10.1001/archdermatol.2012.1892.
eAppendix. The Person-Centred Dermatology Self-Care Index (PeDeSI): A Tool to Measure Education and Support Needs in Long-term Skin Conditions
Cowdell F, Ersser SJ, Gradwell C, Thomas PW. The Person-Centered Dermatology Self-Care IndexA Tool to Measure Education and Support Needs of Patients With Long-term Skin Conditions. Arch Dermatol. 2012;148(11):1251-1256. doi:10.1001/archdermatol.2012.1892
Author Affiliations: Faculty of Health and Social Care, University of Hull, Hull, East Yorkshire (Drs Cowdell and Ersser), Department of Dermatology, Nottingham University Hospitals National Health Service Foundation Trust, Nottingham (Ms Gradwell), and Clinical Research Unit, Bournemouth University, Dorset (Dr Thomas), England.
Objective To validate the Person-Centered Dermatology Self-Care Index (PeDeSI) as a tool for clinical assessment and for potential use in research evaluation.
Design To date, no validated assessment measures exist to identify the education and support needs of patients living with long-term dermatological conditions and to enable them to self-manage as effectively as possible. The PeDeSI assessment tool was developed to meet this need using the self-efficacy construct and a model of concordance within prescribing practice. In total, 200 copies of the PeDeSI were distributed for validation, and 145 (72.5%) were returned completed. Data were analyzed using statistical software. Frequency distributions of all items were examined, and internal consistency was summarized using Cronbach α. Exploratory factor analysis was used to disclose any underlying structure among the data items.
Setting Three specialist dermatology centers in acute care hospitals.
Participants Dermatology specialist nurses treating patients with chronic dermatoses.
Intervention A PeDeSI was completed with each patient during his or her usual outpatient consultation.
Main Outcome Measure Cronbach α.
Results Cronbach α was 0.90, indicating good internal consistency. Eliminating individual items in turn made little difference in Cronbach α (range, 0.89-0.90). Item total correlations ranged from 0.44 to 0.76 (median, 0.68). Exploratory factor analysis extracted just one factor (eigenvalue, 5.37), with no other factors having eigenvalues exceeding 1.00. Factor loadings on individual items ranged from 0.47 to 0.80.
Conclusion The PeDeSI is a valid, reliable, and clinically practical tool to systematically assess the education and support needs of patients with long-term dermatological conditions and to promote treatment concordance.
In the United States, a national data profile on skin disease has not been conducted since the late 1970s; however, it is estimated that about 66% of the population have a skin problem at any one time.1 Survey results suggest that approximately 54% of the United Kingdom population experience a skin condition in any year.2 Self-management of long-term conditions is a health policy priority.3,4 Many patients with skin conditions, particularly those with chronic dermatoses, are expected to self-manage.5 However, few studies6,7 have examined self-management in dermatology, and they were small.
Self-management has a fundamental role in controlling skin conditions and in maintaining quality of life,7 but the education and support required to enable patients to gain greater independence are often not systematically or adequately assessed, planned, or evaluated.8 Specifically, tools to assess individual needs are lacking. The tools now used in dermatology are outcome measures, such as quality of life (eg, the Dermatology Life Quality Index9) or severity (eg, the Psoriasis Area and Severity Index10), and are not process measures that may assess key factors influencing such outcomes. Effective chronic disease intervention should begin with an assessment of prior knowledge,11 personal competence,12 and patient-identified outcomes.13 Therefore, a tool to measure self-care ability could provide the basis for developing more tailored and effective programs of education and support.
The objective of this research was to test the validity and reliability (internal consistency) of the Person-Centered Dermatology Self-Care Index (PeDeSI). The study examined the ability and usefulness of this tool in everyday clinical practice to assess the education and support needs of patients with chronic dermatological conditions.
The prototype 23-item PeDeSI was developed by a group of dermatology specialist nurses (C.G. and her colleagues) based on their experience and expertise (C.G., unpublished index, 2005). It was used in practice but was not validated. The next iteration, the 22-item PeDeSI1, was developed by the research team (F.C. and S.J.E.) and by an expert panel (including C.G.) of physicians and nurses, educationalists, and patient representatives (the patients had long-term skin conditions) using the robust theoretical underpinnings of the self-efficacy construct,14 and a model of concordance within prescribing practice15 (eAppendix). Field testing demonstrated that the PeDeSI1 was valid and reliable but was too long for use in everyday clinical practice. Therefore, the PeDeSI2 was developed and tested.
The PeDeSI2 (Figure) was developed by reducing the number of items in the PeDeSI1 from 22 to 10 using expert qualitative clinical judgment (face validity) of a panel consisting of 2 skin care researchers (F.C. and S.J.E.), 1 dermatology specialist nurse (C.G.), and a patient representative, together with feedback from the nurses who had field tested the PeDeSI1. Particular emphasis was placed on removing items that had the least direct consequence for self-care. The final question on the PeDeSI2 is a summary question that is intended to stimulate discussion and understanding between the patient and the physician or nurse.
A National Health Service Research Ethics Committee approved the study. Fifty copies of the PeDeSI2 were sent to 2 dermatology units and 100 copies were sent to a larger unit, with 200 distributed for validation overall in the United Kingdom. The theoretical basis of the tool and its significance were explained to physicians and nurses in a concise accompanying user's guide. In total, 145 copies (72.5%) were returned completed, having been used among patients with a range of skin conditions that included chronic plaque psoriasis, lichen planus, eczema, and ichthyoses. The development methods used helped to ensure good face, content, and construct validity (eAppendix). All the copies of the PeDeSI2 were completed by dermatology specialist nurses in collaboration with patients. Noncompletion was reported as being due to workload and a lack of appropriate patients. No formal sample size calculation was conducted, although various rules about the ratio of patients to items (ratio, 14.5) and the ratio of variables per factor (ratio, 10.0) were satisfied.16,17
The primary outcome was Cronbach α, a measure of internal consistency and the degree to which the items measure the same thing. Cronbach α values of 0.70 or higher are acceptable for research purposes, and values of 0.90 and higher are acceptable for clinical purposes.18 Exploratory factor analysis was used to disclose any underlying structure among the data items by identifying the number of underlying constructs (factors) using “rotation” to assess which items fall within each factor (if >1 factor) and then interpreting the factor. The number of factors was determined by inspection of the amount of variance explained by each possible factor in relation to the total variance of all items (eigenvalues). Factors with eigenvalues exceeding 1.00 explain more variance than the individual items and are considered useful. Factor loadings were calculated, and loadings of 0.40 or higher are thought to signify items that contribute to the factor in a meaningful way.19 Frequency distributions of all items were inspected to assess the extent to which respondents used the full range of the scale. Consideration of the scree plot and eigenvalues were used to determine the number of factors. Data were analyzed using commercially available statistical software (SPSS version 16; SPSS Inc).20
Apart from the data about obtaining repeat prescriptions, analysis of the PeDeSI2 demonstrated that for each item the respondents used the full-scale range of items from 0 to 3, indicating the level of support and education required. The percentage of respondents with scores indicating at least sufficient ability to self-care ranged from 55.2% (“Do you know what the common side-effects of your treatment(s) are?”) to 93.8% (“Do you know how to obtain a repeat prescription?”). Cronbach α was 0.90, indicating good internal consistency for research and clinical purposes. Eliminating individual items, in turn, made little difference in Cronbach α (range, 0.89-0.90) (Table). Item total correlations ranged from 0.44 to 0.76 (median, 0.68). Exploratory factor analysis extracted just one factor (eigenvalue, 5.37), indicating that the scale is a unidimensional construct interpreted as the self-care ability of patients living with chronic dermatoses. Factor loadings on individual items ranged from 0.47 to 0.80, indicating that all the items contributed to the factor in a significant way and that none needed to be discarded. The factor loading for the final question (“Do you feel confident to use treatment(s) at home yourself?”) was 0.74, indicating good correlation between this summary variable and the overall factor. Nurses reported that the completion of the PeDeSI2 could be incorporated into their usual appointment timescales.
The prototype PeDeSI was judged by nurses to be useful in practice but needed to be revised and tested to ensure validity and clinical manageability. The PeDeSI1 provided useful assessment but was too lengthy to be of practical value. To be successful, measures must be feasible for use and be easy to understand, clear, and unambiguous.21 In addition, a more robust theoretical underpinning of the prototype was needed. The self-efficacy construct14 and the concordance model15 provide an evidence base for interventions designed to support self-management and have been used successfully in their application to other long-term conditions.22,23 Improving self-efficacy is vital to enhancing self-management, necessitating a more systematic assessment that positively facilitates agreement and understanding between the patient and the physician or nurse.
Including an action plan in which realistic patient-determined goals are agreed on, documented, and reviewed in true partnership interaction style ensures that the needs of patients are most likely to be achieved. It is useful to have a template for the action plan and to enable participants to consider carefully what they really want to achieve; these goals often differ substantially from those anticipated by physicians and nurses.
The process of using the PeDeSI2 helps to integrate the principles of self-management and concordance in consultations. Each question is designed to address the key issues of knowledge, skills, and confidence, and the action plan encourages the patient and the physician or nurse to agree on realistic goals. The concordance process is supported because optimal use of the tool requires collaboration through discussion of a patient's self-management understanding and capacity.
The PeDeSI2 is unidimensional, has good content and construct validity, and demonstrates high levels of internal consistency. This shorter index can readily be integrated into clinic consultations, and anecdotal feedback suggests that patients, physicians, and nurses found it to be a useful tool to guide outpatient encounters. Indeed, it has been adopted by the study centers included herein and other clinical areas following dissemination. The objective of the use of the index is to help patients, physicians, and nurses work collaboratively to assess the education and support required to enhance self-management. Further research will be needed to evaluate whether accurate assessment of education and support needs translates into the behavioral change required for improved self-management.
Limitations to this work include logistical factors that prohibited the collection of detailed demographic data from patients and workload pressures of participating physicians and nurses that prevented assessment of test-retest reliability. Both of these elements require further testing.
The PeDeSI2 may allow physicians and nurses to make timely, systematic, and accurate assessments of the education and support needs of patients with long-term dermatological conditions and act as a vehicle for actively engaging patients in the concordance process to improve adherence with treatment recommendations. The index also provides a basis for evaluating the effectiveness of measures to support self-management: a crucial factor in treatment efficacy.
Correspondence: Fiona Cowdell, DProf, RN, BA(Hons), MA, Department of Faculty of Health and Social Care, University of Hull, Room 204 Derne Building, Hull, East Yorkshire HU6 7RX, England (firstname.lastname@example.org).
Accepted for Publication: May 3, 2012.
Author Contributions: Drs Cowdell, Ersser, and Thomas had full access to all the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis. Study concept and design: Cowdell, Ersser, Gradwell, and Thomas. Acquisition of data: Cowdell. Analysis and interpretation of data: Cowdell, Ersser, Gradwell, and Thomas. Drafting of the manuscript: Cowdell. Critical revision of the manuscript for important intellectual content: Cowdell, Ersser, Gradwell, and Thomas. Statistical analysis: Thomas. Study supervision: Ersser. Obtain funding: Cowdell, Ersser, Gradwell, and Thomas.
Conflict of Interest Disclosures: None reported.
Funding/Support: This study was supported in part by unrestricted funding from the British Dermatological Nursing Group, the Skin Care Campaign, Pierre Fabre, and LeoPharma.
Role of the Sponsors: The sponsors had no role in the design or conduct of the study; in the collection, analysis, or interpretation of data; or in the preparation, review, or approval of the manuscript.
Additional Contributions: We are indebted to the specialist nurses and patients who tested the PeDeSI2 in practice and to the funders of the study.