Table 5.

Confirmatory analysis for idiopathic calcium stone formers – linear regression analysis

Outcome variables	N obs	Vitamin D Metabolite Diagnostic Ratio
		β	95% CI	P-value
Blood parameters
Total plasma calcium, mmol/L	606	0.014	0.003, 0.025	0.011
Ionized calcium, mmol/L	379	0.009	0.001, 0.016	0.025
Phosphate, mmol/L	607	−0.007	−0.024, 0.009	0.398
b1,25(OH)2 Vitamin D3, pmol/L	605	0.060	−0.111, 0.23	0.491
aIntact PTH, ng/L	593	0.002	−0.039, 0.042	0.938
Urinary parameters
aUrinary calcium, mmol/24h	607	0.077	0.018, 0.136	0.011
bFractional excretion of calcium, %	601	0.051	0.01, 0.093	0.016
aRSS for calcium oxalate	504	0.051	−0.045, 0.148	0.298
aRSS for brushite	501	0.071	−0.076, 0.217	0.345
DEXA parameters
bLumbar BMD, g/cm2	232	−0.007	−0.018, 0.004	0.189
bFemoral BMD, g/cm2	233	−0.018	−0.030, −0.007	0.002

BMD, bone mineral density; BMI, body mass index; dRTA, distal renal tubular acidosis; eGFR, estimated glomerular filtration rate; PTH, parathyroid hormone

Number of observations (N obs), beta coefficients (β), 95% confidence intervals (95% CI) and P-values are indicated for each comparison.

Multivariable association between Vitamin D metabolite diagnostic ratio with clinical traits as outcome variables, adjusted for age, sex, BMI, eGFR, 25(OH) vitamin D₃, urinary sodium excretion, month of VMDR measurement, loop and thiazide diuretics, and medications that interfere with plasma 25(OH) vitamin D3 concentration. Non-calcium stone formers, patients without available stone analysis and with secondary causes for kidney stones were excluded (primary hyperparathyroidism, sarcoidosis, complete dRTA, primary or enteric hyperoxaluria

^anatural logarithm transformed

^bsquare root transformed