Higher Risk of Incident Kidney Stones in Patients with Metabolic Acidosis and CKD
Bibliographic record
Abstract
Background: Epidemiological studies have shown an association between kidney stones and risk for CKD and its progression. Some types of stones are less likely to form at higher urine pH. Metabolic acidosis is a risk factor for CKD progression, but the association of serum bicarbonate with risk of incident kidney stones is not well understood. Methods: Optum's de-identified Integrated Claims-Clinical dataset of US patients (2007-2019) was queried to identify patients with non-dialysis CKD stages 3-5 with 2 consecutive serum bicarbonate values of 12 to <22 mEq/L (metabolic acidosis) or 22 to <30 mEq/L (normal serum bicarbonate) with data ≥3 years pre-index. The first qualifying serum bicarbonate test established the index date. Primary exposure variables were baseline serum bicarbonate and change in serum bicarbonate over time. Adjusted timedependent Cox Proportional Hazards models were performed to evaluate time to first occurrence of kidney stones (by ICD-9 or ICD-10 diagnosis codes) during an average 3.6 year follow-up period. Other covariates included age, sex, race-ethnicity, education and income status, history of kidney stones, pre-index comorbidities associated with kidney stones, bariatric surgery, obesity, smoking history, baseline eGFR. Results: 142,904 patients qualified for the study cohort. Patients with metabolic acidosis at index experienced kidney stones at greater frequency than those with normal serum bicarbonate at index (12% vs 9%, p<0.0001). Other significant factors associated with incident kidney stones included male sex, history of kidney stones, hyperoxaluria, gout and osteoporosis. Both higher serum bicarbonate at baseline (HR 0.956, 95% CI: 0.948-0.964) and higher serum bicarbonate over time (HR 0.968, 95% CI: 0.961-0.974) were associated with reduced risk of kidney stone development. The observed associations were unchanged in analyses examining death as a competing risk. Conclusions: In patients with CKD, metabolic acidosis (vs. normal serum bicarbonate) was associated with a higher incidence of kidney stones and shorter time to incident stone formation. Future investigations should evaluate these associations by stone type. Funding: Commercial Support - Tricida, Inc.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".