Systematic reviewindependent cross-checkabstract checked★ key study I-VEG-120 standard review
Oxalate kidney damage is rare but severe
Secondary Oxalate Nephropathy: A Systematic Review.
Overview
Lumlertgul N et al.. Kidney Int Rep 2018 · PMID 30450463 · DOI 10.1016/j.ekir.2018.07.020
Among 108 published cases of secondary oxalate nephropathy, excessive dietary oxalate was a cause in about 1 in 5; over half needed dialysis.
Does the study support the specific claim? Yes · Methodological quality: low
Plain-language summary
Study explained simply
- What did the researchers want to find out?
Describe secondary oxalate nephropathy.
- How was the study done?
Systematic review of case reports.
- How many people, animals or samples were studied?
108 patients.
- What was actually found?
Rare, severe; diet one of several causes.
- How large was the observed effect?
55% dialysis; 33% died.
- What do the results mean in everyday life?
Extreme oxalate intake can harm kidneys, especially in people with other risks.
- What are the study's limitations?
Case reports only.
- What does it say about Elawady's specific claim?
Supports the juicing-risk claim.
- Do the results apply to Germany and Europe?
Universal.
- What can explicitly not be concluded from this study?
Cannot estimate risk per person.
Scientific in-depth review
1. Full reference
- Authors
- Lumlertgul N et al.
- Journal
- Kidney Int Rep
- Year
- 2018
- Identifier
- PMID 30450463 DOI 10.1016/j.ekir.2018.07.020
- Verification
- verified – PubMed efetch 2026-10-26; Crossref 2026-10-26
- Retracted
- no
- Corrections
- none
- Extent checked
- abstract only
- Conflicts of interest and funding
not stated in abstract
2. Research question
What are the clinical characteristics and outcomes of secondary oxalate nephropathy?
3. Study design and population
- Study design
- Systematic review – Systematic review of case reports and case series (with meta-analysis of case series)
- Population
Biopsy-proven oxalate nephropathy (native or transplant kidneys)
- Country
Multiple
- Period
1950-January 2018
- Sample size
57 case reports + 10 case series; 108 patients
- Inclusion and exclusion criteria
not stated in abstract
4. Methods and endpoints
- Exposure / intervention
Causes of hyperoxaluria incl. excessive dietary oxalate
- Comparator
none
- Endpoints
Kidney function, dialysis, death
- Statistical methods
Descriptive; meta-analysis of case series
5. Actual results
- Results
Mean age 56.4; fat malabsorption attributed in 88%, excessive dietary oxalate in 20% (causes overlap); peak creatinine 4.6 mg/dl; 55% required dialysis; none fully recovered; 58% remained dialysis-dependent; 33% died.
- Absolute risks
not reported
- Authors' conclusion
Secondary oxalate nephropathy is rare but potentially devastating; preventive strategies are needed in high-risk patients.
6. Strengths
- Systematic search over seven decades
7. Weaknesses
- Case reports: publication bias toward severe cases; no denominator
8. Risk of bias
- Orienting tool
- AMSTAR 2
- Type of assessment
- simplified assessment (abstract only)
- Full formal assessment
- no
- Overall risk of bias
- some concerns
- Rationale
Synthesis of case reports.
9. Assessment of the statistical interpretation
About 22 of 108 cases had dietary oxalate as an attributed cause (stats/C-VEG-06_oxalate_nephropathy.py).
10. Relevance to the specific claim
Supports that excessive dietary oxalate can contribute to severe kidney injury, usually with other risk factors.
11. Independent contrary findings
No incidence data; normal intake not implicated.
12. Transferability to Germany and Europe
Universal.
13. Overall methodological judgement
Supports the conditional claim (extreme intake, susceptible people).
| Multidimensional assessment | |
|---|---|
| Authenticity of the source | verified |
| Methodological quality | low |
| Risk of bias | some concerns |
| Precision of results | not applicable |
| Directness | direct |
| Reproducibility | partly replicated |
| Consistency with the overall evidence | consistent |
| Regional transferability | high |
| Adequacy of the interpretation (by the archive) | not applicable |
14. Open questions
Incidence among juicers.