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Anal Fistula Patients: A Quality Of Life Tool

Anal Fistula Patients: A Quality Of Life Tool


The study aims to address the lack of quality of life (QoL) measurement instruments tailored specifically for patients with cryptoglandular anal fistula.

Through a comprehensive approach involving qualitative patient interviews, systematic review of existing instruments, and expert input, a novel measurement instrument was developed.

This 22-item instrument, scored on a scale from 0 to 100, demonstrates robust psychometric properties. It exhibits excellent internal consistency (Cronbach-α= 0.927), strong content and construct validity, and high reliability and responsiveness.

The instrument’s ability to accurately assess QoL in patients with cryptoglandular anal fistula was validated through its correlation with relevant clinical measures, such as the Perianal Disease Activity Index and Hospital Anxiety and Depression scales.



Colorectal research has long been dedicated to understanding the intricacies of cryptoglandular anal fistula, a condition fraught with challenges in both assessment and management. Despite the medical community’s attention to this ailment, there has been a notable oversight concerning its profound impact on patients’ quality of life (QoL).

Recent insights from a consensus of international experts, including patients, researchers, and clinicians well-versed in managing anal fistula, have shed light on the critical importance of measuring QoL in all studies evaluating fistula treatments.


Regrettably, studies addressing QoL in this context have been sparse, with a mere 14% of them incorporating QoL metrics as outcomes. Furthermore, when QoL has been assessed, it has typically been done using generic measurement tools.

These instruments have revealed a stark reality: individuals living with a fistula experience a diminished QoL compared to the general population. Notably, the presence of fecal incontinence, a common consequence of fistulas, has been found to correlate with a decline in QoL.


However, the relationship between QoL and fecal incontinence is nuanced. Studies have demonstrated varying outcomes based on the severity of incontinence.

While patients with minor impairment may not experience a significant reduction in QoL following treatment or fistula closure, those with severe deterioration in continence after surgery often report a notable decline in QoL.

This complexity highlights the inadequacy of using continence alone as a surrogate marker for QoL, emphasizing the need for more comprehensive assessment tools.


Recognizing these limitations, there is a clear call for the development of disease-specific instruments that possess greater sensitivity to changes in QoL and can accurately capture the impact of fistulas and their treatment on patients’ lives.

Despite efforts to design disease-specific tools for cryptoglandular anal fistula, existing instruments have faced criticism for their lack of patient involvement in development and failure to fully capture the multifaceted impact of the disease.

In response to this pressing need, the present study aimed to develop a patient-centered Anal Fistula Quality of Life (AF-QoL) assessment tool specifically tailored for individuals grappling with cryptoglandular anal fistula.

By engaging patients in the development process and addressing the shortcomings of current instruments, the AF-QoL tool seeks to provide a more accurate reflection of the lived experiences of fistula patients, thereby enhancing content validity and ultimately improving clinical outcomes.



The study on the development of the Anal Fistula Quality of Life (AF-QoL) scale was conducted in line with the meticulous standards set forth by the COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN) for the development of patient-reported outcome measures (PROMs). Ethical approval was diligently obtained from esteemed research ethics committees, ensuring strict adherence to ethical guidelines throughout the entire research process.


A proficient study management team, comprised of experienced colorectal surgeons, qualitative researchers with expertise in PROM development, and patient representatives, meticulously oversaw the development of the AF-QoL scale. This team ensured that the construct of Quality of Life (QoL) was meticulously defined to encompass the subjective evaluation of the direct impact of having a fistula or undergoing treatment on an individual’s overall well-being, aligning with the principles of PROM development.


The AF-QoL instrument was meticulously designed to center around the unique challenges faced by individuals dealing with cryptoglandular anal fistula. The target population encompassed patients across a spectrum of disease complexities and durations, with the exclusion of individuals with Crohn’s anal fistula. To ensure a comprehensive representation of the disease’s diverse manifestations, a purposive sampling strategy was employed during participant recruitment.


The study progressed through several pivotal stages, commencing with the generation of items through qualitative interviews and an exhaustive review of existing measurement instruments. Subsequently, cognitive interviews were conducted to refine the initial draft questionnaire, meticulously evaluating the clarity and relevance of each item. The content validity of the instrument was rigorously assessed by independent experts, with items lacking sufficient relevance being systematically excluded from the final scale.


Following item reduction, the AF-QoL instrument underwent rigorous psychometric analysis to evaluate internal consistency, construct validity, and reliability. Principal component analysis (PCA) was meticulously utilized to identify potential subscales within the AF-QoL instrument, providing further insights into its structural composition. Moreover, the final instrument underwent comprehensive testing for floor and ceiling effects, test-retest reliability, and responsiveness to changes in symptomatology.


To enhance the interpretability of the AF-QoL scale, self-reported visual analogue scores were meticulously utilized to determine the minimally important change (MIC), offering valuable insights into clinically significant differences. Lastly, the retained items of the AF-QoL instrument underwent meticulous scrutiny by the study management group to ensure their clinical relevance, readability, and overall acceptability within the target population.


The study engaged 148 patients across its various phases, aimed at developing and validating the Anal Fistula Quality of Life (AF-QoL) scale. Beginning with interviews from 10 patients, the researchers identified key themes related to physical symptoms, treatment experiences, and the impact on daily life. These insights were instrumental in crafting an initial draft of the AF-QoL scale, consisting of 44 items.


Subsequent cognitive interviews involving 18 participants helped refine the wording and structure of the scale, resulting in the inclusion of six additional questions to enhance its comprehensiveness. Content validity assessment by seven experts further refined the scale, retaining 39 items for further testing.


Psychometric testing involved 120 participants completing the AF-QoL alongside validated measures, revealing insights into the participants’ quality of life, which appeared lower than average based on SF-12 scores. Scoring the AF-QoL involved averaging applicable responses on a scale ranging from 0 to 100, where higher scores indicated better quality of life.


Through iterative item reduction processes based on item-total and item-item correlations, the scale was refined to a 22-item version, maintaining robust internal consistency and construct validity. Principal component analysis unveiled six distinct factors within the scale, covering various facets of the fistula experience, from psychological impacts to practical limitations.


Retest analysis involving 78 participants demonstrated the scale’s stability and reliability, with an excellent correlation between test and retest scores. Moreover, the scale exhibited responsiveness to changes in symptom severity, as indicated by acceptable effect sizes and response ratios.


The study also determined the minimal important change (MIC) for the AF-QoL scale, establishing a benchmark for interpreting meaningful shifts in quality of life scores. This meticulous process culminated in the development of a concise, yet comprehensive instrument tailored specifically to assess the quality of life in individuals with cryptoglandular anal fistula, offering clinicians and researchers a valuable tool for evaluating treatment outcomes and patient well-being.



Existing quality of life (QoL) measurement tools have often lacked sufficient input from patients, which raises concerns about their content validity.

The Anal Fistula Quality of Life (AF-QoL) instrument addressed this issue by actively involving fistula patients in its development, resulting in a comprehensive range of topics that reflect their experiences.

Although participants varied in disease duration and treatment history, efforts were made to ensure that all relevant themes were captured throughout the study stages.


Balancing comprehensiveness with instrument length posed a challenge, but statistical analyses effectively removed redundant items, resulting in a concise 22-item instrument. This final version encompasses all essential QoL aspects identified in recent core outcome sets.

The inclusion of conditional themes in the instrument necessitated careful consideration of missing data handling methods. Inapplicable questions were omitted from the QoL score calculation rather than substituted with arbitrary values to ensure accuracy.


The study’s strengths lie in its patient-centered approach, with expert clinicians and researchers guiding the methodology according to rigorous standards.

This multidisciplinary approach ensured the instrument’s validity, specificity to the domain, and excellent internal consistency and construct validity. However, some limitations exist in AF-QoL development, which warrant consideration.


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