Content Analysis of Patient-Reported Outcome Measures Used in Patients With Nail Conditions

Abstract

This systematic review identifies and examines the content of nail-specific patient questionnaires to understand if some instruments may be better suited to measuring different research outcomes.

Nail conditions are associated with a patient’s physical, psychological, and social challenges in daily life.¹ Patient-reported outcome measures (PROMs) can capture these constructs and aid in clinical decision-making and treatment evaluations. The objectives of this study were to identify nail-specific PROMs and describe the concepts measured by these tools.

Methods

A systematic review was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) reporting guidelines as part of a 3-part project to comprehensively assess nail-specific PROMs. Ethics approval was not required because the study reviewed only existing literature.

The systematic review methods have been described elsewhere²; the search was updated in January 2021. Content (items/stems) and response options for PROMs underwent content analysis that considered each item and applied 3 levels of codes: (1) major domain; (2) subdomain; and (3) health concept. A consensus meeting was held to review codes and ensure coding consistency. The coding framework was informed by the Patient-Reported Outcomes Measurement Information Systems.³ Items were categorized according to whether their phrasing or content were negative, positive, or neutral. The characteristics of nail-specific PROMs are summarized in eTable 1 in the Supplement.

Data analysis was conducted from May to June 2021 using Excel, MS Office 365 (Microsoft). This was a qualitative analysis that did not use statistical techniques.

Results

A total of 209 publications met inclusion criteria. Eight nail-specific PROMs were retrieved from across 36 publications; however, the Health-Related Quality of Life Measure for Onychomycosis by Lubeck and colleagues was excluded because it could not be obtained for review.² The remaining 7 nail-specific PROMS contained a total of 175 items. Because 10 (6%) of these items comprised more than 1 health concept, they were counted as 2 items. For example, the item “my nail is thick and discolored” was coded as both “thick” and “discolored.” The total of 194 health concepts were categorized into 5 domains (appearance, psychological wellbeing, physical wellbeing, nail care, social wellbeing), 18 subdomains, and 67 unique health concepts.

Physical and psychological concerns were the most frequently measured concepts, with 51 (26.3%) and 50 (25.8%) items, respectively. Few items measured nail appearance (n = 32; 16.5%), physical concerns (n = 19; 9.8%), or nail care (n = 17; 8.6%). Five PROMs covered all 5 domains; however, not all domains were comprehensively measured (Figure 1).

Figure 1. Content Analysis of Nail-Specific Patient-Reported Outcome Measures (PROMs).

NailQoL refers to the Nail Quality of Life questionnaire; NAPPA-PBI, the Nail Assessment in Psoriasis and Psoriatic Arthritis–Patient Benefit Index; NAPPA-QoL, the Nail Assessment in Psoriasis and Psoriatic Arthritis–Quality of Life; NPQ10, the Nail Psoriasis and Quality of Life measurement; ODSQ, the Onychomycosis Disease-Specific Questionnaire; ONYCHO, the Onychomycosis Quality of Life Questionnaire; and OnyCOE-t is this instrument’s trademarked name.

Within the PROMs, 68.6% (120 of 175) of the items were negatively phrased or had negative content. The Nail Quality of Life (NailQoL) questionnaire had the greatest proportion of items with negative phrasing or content (14 of 15 items; 93%). Negative wording, which focuses on patients’ perceived difficulties and concerns, may adversely affect patients’ understanding of the condition and how they think about themselves.⁴

Discussion

This systematic review outlined the content of nail-specific PROMs to help guide selection for use in research and clinical practice. These PROMs were mainly developed for use in managing nail psoriasis or onychomycosis, with unknown validity to other nail conditions. Items were mostly focused on physical, social, and psychological concerns; few items addressed nail appearance and care. The 67 unique health concepts we identified indicate substantial heterogeneity both within and between PROMs (Figure 2). Heterogeneity may limit the ability of a PROM to comprehensively measure a concept of interest, and overall scores based on multiple concepts can be difficult to interpret.

Figure 2. Conceptual Framework Based on the Analyzed Contents of Patient-Reported Outcome Measures Used for Patients With Nail Conditions.

HRQL denotes health-related quality of life; characteristic refers to nail traits, eg, uneven, too short; change means change over time, ie, the condition becoming better or worse; positive refers to positive influence, eg, more content/pleased; and relationship encompasses social connections with family, friends, and/or a partner.

When choosing a PROM for patients with nail conditions, the relevance of the items to the concept of interest, target population, and context of use should be considered. Certain PROMs may be better suited for different clinical circumstances or research purposes. For example, the NailQoL measures quality of life using 4 domains—social, psychological, treatment, and physical²—and does not include any items regarding appearance. If nail appearance is a key outcome of the study, the NailQoL may not be the best choice for a PROM tool. To measure nail appearance and psychological outcomes, researchers may find the survey developed by Drake and colleagues, the Onychomycosis Quality of Life Questionnaire, to be the most comprehensive instrument.² For measuring social well-being and physical function, researchers may consider the Onychomycosis Disease-Specific Questionnaire, which has the most items regarding these concepts.²

This study had a number of limitations. Regarding the search strategy, only 2 databases were searched thoroughly (EMBASE and MEDLINE). Additionally, being unable to review the questionnaire by Lubeck and colleagues was a potential limitation to the content analysis. Searching additional databases for nail-specific PROMs could benefit future investigations.

Measurement of patient concerns associated with nail conditions would benefit from further qualitative research involving patients. Additional research would aid in identifying the health constructs that are most relevant to patients with a broad range of nail conditions and would enhance the conceptual clarity of PROMs.

Supplement.

eTable 1. Characteristics of nail-specific patient-reported outcome measures