Compliance in patients with dietary hyperoxaluria: A cohort study and systematic review

Abstract

Objective Hyperoxaluria leads to calcium oxalate crystal formation and subsequent urolithiasis. This study aims to analyse the effect of treatment compliance in hyperoxaluria, firstly by analysis of patients with non-primary hyperoxaluria and secondly via systematic review in patients with any hyperoxaluria. Methods In a retrospective cohort study, adults with non-primary hyperoxaluria managed with dietary counselling in 2013 were enrolled. Twenty-four-hour (24 h) urine collections initially and at 6 months were obtained. Compliance was assessed by self-reported dietary compliance and 24 h urinary volume >2 L. Patients were followed for 24 months. Primary outcomes were urinary oxalate and calcium 24 h load at 6 months, and urolithiasis-related procedural rates at 24 months. A Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA)-compatible systematic review of compliance among hyperoxaluric patients was performed. Results In the cohort study, of 19 eligible patients (4 female) with median age 52 years, 10 (53%) were considered compliant. Compared with the non-compliant group, these patients had significantly increased subsequent 24 h urinary volume (2250 mL vs. 1600 mL; p = 0.008) and lower procedural rates (10% vs. 56%; p = 0.033). Subsequent 24 h urinary oxalate load was non-significantly lower in compliant patients. Systematic review regarding compliance in hyperoxaluric patients revealed five studies. Only one utilised dietary counselling or analysed compliant vs. non-compliant patients, finding no difference. None examined the effect of compliance on procedural rates. Conclusion Hyperoxaluria is an important cause of recurrent urolithiasis. Increasing fluid intake and reducing dietary oxalate reduce the risk of operative intervention and remain fundamental to the treatment of hyperoxaluria.

Impact of low‐oxalate diet on hyperoxaluria among patients suffering from nephrolithiasis

“…The majority of individuals do not necessitate apprehension regarding the presence of oxalate in their dietary intake. Nevertheless, in the event that an individual has previously had oxalate kidney stone, it is advised adhering to a low‐oxalate dietary regimen in order to mitigate the likelihood of recurring episodes of kidney stone formation, which may be highly distressing (Hennessey et al., 2019 ). Blood tests are employed to assess renal function and quantify oxalate concentrations in the bloodstream, for this purpose blood oxalate test was done at initial and final trial day to measure the amount of oxalate in blood which involved in causing hyperoxaluria shown in Table 3 .…”

Impact of the adherence to medical treatment on the main urinary metabolic disorders in patients with kidney stones

“…Allopurinol has been indicated for the treatment of calcium oxalate stones associated with hyperuricosuria; its use has shown up to a 50% decrease in the recurrence of lithiasis vs. placebo [ 20 ]. In hyperoxaluria, the reduction of dietary oxalate is essential; only 52% of patients have adequate compliance with dietary measures and fluid consumption, achieving a significant decrease in urinary oxalate levels [ 16 , 21 , 22 ].…”

“…The study was conducted in a third level hospital, with a specialized lithiasis clinic, in which complex and recurrent cases of kidney stones are treated so that it could be not representative of the general population. Although the follow-up time of our population could be considered a short time follow-up for chronic diseases, all the previous studies evaluating adherence to medical treatment have reported just 6 months of follow-up [ [16] , [17] , [18] ]. Long-term follow-up is necessary to document the constancy to adherence in chronic treatments and to observe changes in the 24-hour urinary metabolic study and its long-term effect on recurrence rate changes, stone re-formation, emergency visits, and even loss of kidney function.…”

“…For patients with two or more alterations of 24-hour urine composition, they received multiple treatments with two or more prescriptions, as well as combined dietary modifications (Supplementary material). Compliance or adherence to dietary modifications was evaluated by self-reported dietary compliance as described by previous authors [ 16 , 17 ].…”