Characterization of Patient-Reported Loin Pain in IgAN

Introduction: Loin pain is a frequently reported symptom in IgA nephropathy (IgAN), but its significance is unclear. No known data exists regarding its prevalence, characteristics, or its impact on daily life, resulting in little support being offered for its management. 

Methods: A UK-wide mixed-methods study was conducted in collaboration with the National Registry of Rare Kidney Diseases (RaDaR). This included an online survey analyzed using descriptive statistics and group mean comparisons with adjustments for multiple comparisons. In addition, separate semistructured interviews were analyzed with reflexive thematic analysis and applied to the framework of the survey findings. 

Results: A total of 358 patients with biopsy-proven IgAN completed the survey. Twenty-one completed the semistructured interviews. Loin pain was highly prevalent among those surveyed (n = 254, 70.9%). The pain was described predominantly as “aching” (n = 190, 83%) and intermittent (n = 171, 70.4%), with episodes consistent in character but distinct from other causes of pain. The pain appeared independent of chronic kidney disease (CKD) stage. It was associated with systemic symptoms (assessed using the Kidney Symptom Questionnaire). Those with recent pain (within the last month) reported poorer ratings in health, mental health, and self-efficacy, and felt that health care professionals (HCPs) offered little support to manage their pain effectively. 

Conclusion: Loin pain was highly prevalent among patients with IgAN surveyed in the UK. Pain experience was similar and appeared independent of CKD stage. The pain had negative impact on psychosocial wellbeing, and limited support was provided. A need for better understanding of the pain and suitable management strategies was expressed by patients with IgAN.