Urine pH and Renal Dysfunction

Urine pH and Renal Dysfunction

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Kidney Stones	(1)   Urine pH is of particular interest in stone formers, since it determines the presence of either calcium phosphate or uric acid content in stones. (2)   A rise in incidence of low pH-dependent uric acid stones with age, coinciding with a decrease in the incidence of high pH-dependent phosphate stones. (3)   the inclusion of traditionally understood determinants of urine pH such as urinary buffers, estimates of glomerular filtration, and dietary acid load, but these, taken together, accounted for but a small fraction of the pH fall. (4)   Gastrointestinal anion absorption was the strongest predictor of urine pH in all age groups, as we have previously reported in middle-aged normal men and women. (5)   Obesity and diabetes also lower urine pH (3, 21), the prevalence of both rise with age, and both are higher among uric acid stone formers than other stone formers (39). (6)   Age itself, separate from body mass index, renal function, and gastrointestinal anion absorption, had a large and independent association with urine pH. (7)   In this study of 7,891 stone-forming individuals, urine pH fell with age, most dramatically between the ages of 18 and 55 yr old. (8)   the higher urine pH of women throughout all age groups probably explains their higher kidney stone phosphate content versus men	Am J Physiol Renal Physiol. 2019 Jul 1; 317(1): F65–F72 Cameron J. Menezes,1 Elaine M. Worcester,1 Fredric L. Coe,1 John Asplin,2 Kristin J. Bergsland,1 and Benjamin Ko Mechanisms for falling urine pH with age in stone formers
Kidney Stones (Nephrolithiasis)	(1)   Uric acid nephrolithiasis, a condition associated with a low urinary pH, has been linked to obesity and insulin resistance.  (2)   The prevalence of kidney stone disease in the United States is progressively increasing, paralleling the growing rate of obesity. (3)   urinary pH may be inversely associated to body weight in nephrolithiasis. (4)   Urine pH is inversely related to BMI among patients with urolithiasis. Among patients with urolithiasis, higher BMI will have lower urine pH. This may explain why obesity is associated with an increased risk of nephrolithiasis.	Kidney Int. 2004 Apr;65(4):1422-5 NAIM M. MAALOUF, KHASHAYAR SAKHAEE, JOAN H. PARKS, FREDERIC L. COE, BEVERLEY ADAMS-HUET, and CHARLES Y.C. PAK Association of urinary pH with body weight in nephrolithiasis
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Kidney Stones (Urolithiasis)	(1)  Uric acid (UA) urolithiasis comprises around 5–10% of all stones and can frequently recur. (2)  UA stones form in acidic urine with a pH <5.5, (3)  currently a lack of clear evidence for the method of alkalization of urine and the method of pH measurement.	Translational Andrology and Urology (Vol 8, Supplement 4 (September 24, 2019)) Guido Maarten Kamphuis1#, Jons Wouter van Hattum1#, Prim de Bie2, Bhaskar K. Somani3 Method of alkalization and monitoring of urinary pH for prevention of recurrent uric acid urolithiasis: a systematic review
Kidney Stones	(1)   The urine pH has been observed to be associated with many diseases, i.e. urothelial carcinoma, metabolic disorders, and kidney stone disease (2)   Crystal-cell adhesion assay showed the greatest degree of crystal-cell adhesion at the most acidic pH and least at the most basic pH. (3)   acidic urine pH may promote CaOx kidney stone formation, whereas the basic urine pH (i.e. by alkalinization) may help to prevent CaOx kidney stone disease. (4)   Crystal internalization assayusing fluorescein isothiocyanate (FITC)-labelled crystals and flow cytometry demonstrated that crystal internalization into renal tubular cells was maximal at the neutral pH (7.0).	Nature, Scientific Reports, 2017 May 11;7(1):1798 JuthatipManissorn, Kedsarin Fong-ngern, PaleerathPeerapen&VisithThongboonkerd Systematic evaluation for effects of urine pH on calcium oxalate crystallization, crystal-cell adhesion and internalization into renal tubular cells
Kidney Stones	(1)  Kidney stones are common in industrialized nations: up to 15% of white men and 6% of all women will develop one stone, with recurrence in about half these people. Despite urbanisation of black South Africans, renal stones have been reported in less than 1% of this population. (2)  Up to 75% of stones are calcium oxalate, the others are struvite (magnesium ammonium phosphate, 10–20%), uric acid (5%), 5% contain more than 50% brushite (calcium monohydrogen phosphate) or hydroxyapatite, and less than 1% are composed of cystine (3)  First, uric acid can precipitate in persistently acid urine, even in the absence of hyperuricaemia or hyperuricosuria. Second, uric acid can cause formation of calcium oxalate stones without being incorporated into the crystals. This catalyst-like ability is known as salting out, and is enhanced in acid urine. (4)  Stones smaller than 5 mm normally pass spontaneously, whereas larger stones, as big as 2 cm, are best treated with extracorporeal shock-wave lithotripsy. (5)  Low urine pH is a urinary stone promoter	THE LANCET • Vol 358 • August 25, 2001 Bihl, G. & Meyers, A Recurrent renal stone disease-advances in pathogenesis and clinical management
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Renovascular Disorder	(1)        Decreased UpH, in particular, was a powerful predictive factor for renovascular disorders. UpH is always determined as part of routine testing; it is a non-invasive and inexpensive test. The finding that UpH can predict longterm renovascular disorders has significant clinical value. (2)        A lower urinary pH is closely linked to diabetes, as well as to the exacerbation of diabetic renovascular disorders. (2)        A lower urinary pH is closely linked to the metabolic syndrome and hyperuricemia, and also strongly related to increases in intrarenal oxidative stress. (3) The mechanism that lower urinary pH takes part in the progress of diabetic renovascular disorders has not been clarified. (4) Acidosis takes various forms, such as respiratory acidosis and metabolic acidosis. In diabetics, decreased urinary NH3 contributes to a drop in UpH. (5) Lower urinary pH (UpH), which is common among complicated case patients such as obesity and chronic kidney disease (CKD), contributes to precipitation of uric acid (UA) in the urine. (6) A high-protein diet decreases the secretion of NH3 into the urine, and reduces UpH as a result. The content of the patient’s meal might be a cause of lower UpH. (7) lowered UpH is caused by an increased supply of H+ to the urine or a reduction in the ability to eliminate H+ . An increased supply of H+ to the urine occurs either because of a reduction in blood pH (BpH) or the increased secretion of H+ from the renal tubules, while a reduction in the ability to eliminate H+ occurs as a result of a reduction in the supply of NH3 to the urine.	Susumu Ogawa,1,2 Kazuhiro Nako,1 Masashi Okamura,1 Sadayoshi Ito1 BMJ Open Diabetes Res Care, 2015, 1-7 Lower urinary pH is useful for predicting renovascular disorder onset in patients with diabetes
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Renal function in primary Gout patients	(1)   Out of 11,757 gout patients screened, 3565 patients were selected for analysis (2)   We observed that nearly half of the gout patients had acidic urine, with 16.10% of the patients having urine pH less than 5.0. The proportion of patients with urine pH between 6.2 and 6.9 was 14.45%. Renal damage in gout patients was also closely related to urine pH [30].  (3)   Acidic urine is multifactorial in etiology; in gout patients, urine pH would be anticipated to be significantly influenced by factors including diet, insulin resistance, hydration status, and medications including thiazide diuretics and CKD [11,12,13,14]. (4)   When urine pH is elevated via the supplementation of sodium bicarbonate, the progression of CKD is significantly slowed down [34]. These reports strongly suggest that a lower urine pH is closely linked to the advancement of kidney damage. Our data showed that patients with urine pH < 5.0 was associated with significantly increased proteinuria, microhematuria, renal cyst, and nephrolithiasis. More than 50% of stones in gout patients are uric acid stones in which the driving biochemical abnormalities first include low urine pH [35, 36], but also high urine urate concentration and low volume	Arthritis Research & Therapy volume 24, Article number: 32 (2022) Yuwei He, Xiaomei Xue, Robert Terkeltaub, Nicola Dalbeth, Tony R. Merriman, David B. Mount, Zhe Feng, Xinde Li, Lingling Cui, Zhen Liu, Yan Xu, Ying Chen, Hailong Li, Aichang Ji, Xiaopeng Ji, Xuefeng Wang, Jie Lu & Changgui Li Association of acidic urine pH with impaired renal function in primary gout patients: a Chinese population-based cross-sectional study
Kidney Stones	(1)   Patients with CaHPO4 kidney stones belong to a diagnostic category that has a high urine pH as its common feature There are heterogeneous causes for a persistently high urine pH. (2)   There are heterogeneous causes for a persistently high urine pH (up to 7.5) (3)   Limited no. of cases studied in each category	Nephrol Dial Transplant, 2007 Feb;22(2):424-31