Optimizing Upper-Tract Imaging for Non-Visible Haematuria.

INTRODUCTION: Non-visible haematuria (NVH) is associated with a small risk of upper-tract urothelial carcinoma (UTUC), though there is little consensus on its investigation, particularly with regard to upper-tract imaging. This study aimed to determine whether the presentation of UTUC can guide investigation of NVH in patients under 60 years old. METHODS: All patients investigated at our one-stop haematuria clinics under a cancer pathway were reviewed during a 5-year period, with all patients undergoing cystoscopy and upper-tract imaging. Retrospective analysis of all UTUC cases from our urological cancer multidisciplinary team meeting database over a 10-year period was also undertaken. RESULTS: 2,129 patients with a median age of 67 years underwent urgent investigation for haematuria between March 2015 and February 2020. 449 cases presented with NVH, of whom 124 (27.6%) were under 60. Out of 21 cases of UTUC, only 2 presented with NVH; both were over the age of 60 years. Factors that independently predicted diagnosis with urinary-tract malignancy were age ≥60 (OR 3.70, p < 0.001), visible haematuria (OR 2.50, p = 0.006), and suspicious cystoscopic findings (OR 58.06, p < 0.001). Review of all 119 UTUC cases over 10 years found 6 cases (5.0%) presenting with NVH, with one (0.8%) also presenting under 60 years. CONCLUSION: Diagnosis with UTUC is rare in patients presenting with NVH under the age of 60 years. Routine use of CTU in this low-risk group is best avoided, with ultrasonography constituting a safer first-line upper-tract imaging modality. Guidelines that risk-stratify NVH patients may be effective in reducing unnecessary investigations.

Variation in Tap Water Mineral Content in the United Kingdom: Is It Relevant for Kidney Stone Disease?

Introduction: The dissolved mineral content of drinking water can modify a number of excreted urinary parameters, with potential implications for kidney stone disease (KSD). The aim of this study is to investigate the variation in the mineral content of tap drinking water in the United Kingdom and discuss its implications for KSD. Methods: The mineral composition of tap water from cities across the United Kingdom was ascertained from publicly available water quality reports issued by local water supply companies using civic centre postcodes during 2021. Water variables, reported as 12-monthly average values, included total water hardness and concentrations of calcium, magnesium, sodium and sulphate. An unpaired t-test was undertaken to assess for regional differences in water composition across the United Kingdom. Results: Water composition data were available for 66 out of 76 cities in the United Kingdom: 45 in England, 8 in Scotland, 7 in Wales and 6 in Northern Ireland. The median water hardness in the United Kingdom was 120.59 mg/L CaCO3 equivalent (range 16.02−331.50), while the median concentrations of calcium, magnesium, sodium and sulphate were 30.46 mg/L (range 5.35−128.0), 3.62 mg/L (range 0.59−31.80), 14.72 mg/L (range 2.98−57.80) and 25.36 mg/L (range 2.86−112.43), respectively. Tap water in England was markedly harder than in Scotland (192.90 mg/L vs. 32.87 mg/L as CaCO3 equivalent; p < 0.001), which overall had the softest tap water with the lowest mineral content in the United Kingdom. Within England, the North West had the softest tap water, while the South East had the hardest water (70.00 mg/L vs. 285.75 mg/L as CaCO3 equivalent). Conclusions: Tap water mineral content varies significantly across the United Kingdom. Depending on where one lives, drinking 2−3 L of tap water can contribute over one-third of recommended daily calcium and magnesium requirements, with possible implications for KSD incidence and recurrence.

Does the mineral content of tap water correlate with urinary calculus composition?

The association between the mineral content of drinking water and urolithiasis remains elusive. The aim of this study is to investigate whether the mineral composition of tap water correlates with urinary calculus composition. Patients with calculi that underwent biochemical analysis at two urological centres in the North-West of England between November 2015 and December 2020 were included. Calculus composition was reviewed with respect to patient demographics, serum biochemical variables, and water mineral composition data obtained from the local water supply company using patient postcodes. 1711 urinary tract calculi from 1518 patients, living in 87 water supply zones were included. Water sodium concentration was an independent predictor of mixed calcium oxalate/uric acid calculi (OR 1.157, p < 0.001) and a negative independent predictor of calcium oxalate monohydrate (OR 0.896, p = 0.001) and dihydrate (OR 0.742, p = 0.034) calculi. Moreover, the magnesium-to-calcium ratio of tap water was a negative independent predictor of calcium oxalate monohydrate calculi (OR < 0.001, p = < 0.001), while tap water magnesium concentration inversely correlated with the percentage of calcium oxalate within calculi (rs = - 0.054, p = 0.026). Total water hardness did not independently predict calculus type. Many factors are implicated in the formation of urinary calculi. This study is the first to assess calculus composition in relation to tap water mineral content using postcode data on a case-by-case basis. Though total water hardness did not independently predict calculus composition, the interesting findings relating to water sodium and magnesium concentrations are in need of closer scrutiny in larger scale studies.