Check list for publications about cadmium and chronic kidney disease
Note
1. Reference
2. Reader KB Ho
3. Further publication(s) in the same/partly the same population
4. Place and time
Country/region/institution
Time period
5. Purpose
Short summary of the purpose
Has the purpose determined
-the planning of the study
-the carrying out of the study
-the statistical analysis
The kidney damage was the only a priori purpose of the study
The kidney damage was undoubtedly one a priori purpose of the study but other endpoints
were also used. The other endpoints are
6. Study design
-prospective cohort study
-was there really a medical examination before any exposure to cadmium checking
the factors of susceptibility, initiation or progression?
-otherwise what is the time elapsed between the first exposure to cadmium and the
baseline examination?
-what was measured before any cadmium exposure?
-duration of follow-up (from the baseline to the last examination)
-historic prospective cohort study
-duration of follow-up
-case control study
7. Statistics
-was the normality of the distribution examined?
-are the statistical tests adequate?
-was a multivariable analysis performed?
Power
- are power calculations explicitly mentioned?
8. Funding, academia, occupational health service of the plant, relationship with
employer
9. Study population
-exposed subjects
Age (mean, median, range, percentiles)
Essential issue: were the subjects old enough to have a CRI (the disease
appears late in life)?
Gender (number of males/females)
Nationality/”race” (categories and number in each category)
Socioeconomic level (important because of association with access to health
care and because it is a susceptibility factor for CKD; definition, number in each
category)
Height (mean, median, range, percentiles)
Weight (mean, median, range, percentiles)
BMI (mean, median, range, percentiles)
Smoking (definition, proportions)
Alcohol (definition, proportions)
Diet (definitions, proportions)
Diseases
-Kidney and urinary tract
-Kidney
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Following aspects were specifically searched for
Diabetes
-definition of diabetes (cave: there should have been some confusion. Indeed,
renal glucosuria is not the same as diabetes. However, according to Nishijo et
al. (1995) patients were diagnosed with diabetes although they had a renal
glucosuria only)
-is there a measurement of blood glucose or of glucose tolerance
-how was the diabetes controlled during the follow-up?
Hypertension
-definition (anamnestic / measurement at medical examination / measurement
at medical examination and treatment / familial history
-only anamnestic information / measured BP /
-how was the blood pressure controlled during the follow-up?
-antihypertensive drugs: see Drugs (below)
Cholesterol
- total cholesterol / HDL, LDL
-only anamnestic information / measurement /
-triglycerides
-only anamnestic information / measurement /
Glomerular diseases (infection, autoimmune diseases)
Urinary tract disease (infection, stones, obstruction)
Premature neonate
Reduced renal mass
Coronary heart disease and other clues to arteriosclerosis (arteriosclerosis of
the renal arteries)
Drugs
The following drugs were considered:
There are specific comments about NSAID:
The following specific treatment are considered
Hypertension
- diuretics
- ACE
- others
Family history of kidney disease, genetic factors
-non-exposed subjects
Age (mean, median, range, percentiles)
Essential issue: were the subjects old enough to have a CRI (the disease
appears late in life)?
Gender (number of males/females)
Nationality/”race” (categories and number in each category)
Socioeconomic level (important because of association with access to health
care and because it is a susceptibility factor for CKD; definition, number in each
category)
Height (mean, median, range, percentiles)
Weight (mean, median, range, percentiles)
BMI (mean, median, range, percentiles)
Smoking (definition, proportions)
Alcohol (definition, proportions)
Diet (definitions, proportions)
Diseases
-Kidney and urinary tract
-Kidney
Following aspects were specifically searched for
Diabetes
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-definition of diabetes (cave: there should have been some confusion. Indeed,
renal glucosuria is not the same as diabetes. However, according to Nishijo et
al. (1995) patients were diagnosed with diabetes although they had a renal
glucosuria only)
-is there a measurement of blood glucose or of glucose tolerance
-how was the diabetes controlled during the follow-up?
Hypertension
-definition (anamnestic / measurement at medical examination / measurement
at medical examination and treatment / familial history
-only anamnestic information / measured BP /
-how was the blood pressure controlled during the follow-up?
-antihypertensive drugs: see Drugs (below)
Cholesterol
- total cholesterol / HDL, LDL
-only anamnestic information / measurement /
-triglycerides
-only anamnestic information / measurement /
Glomerular diseases (infection, autoimmune diseases)
Urinary tract disease (infection, stones, obstruction)
Premature neonate
Reduced renal mass
Coronary heart disease and other clues to arteriosclerosis (arteriosclerosis of
the renal arteries)
Drugs
The following drugs were considered:
There are specific comments about NSAID:
The following specific treatment are considered
Hypertension
- diuretics
- ACE
- others
Family history of kidney disease, genetic factors
10. Selection
Exposed subjects
Eligibility criteria
- was any subject or were subjects with possibly existing kidney damage
systematically excluded?
Selection procedure
Participation
Lost cases during follow-up [This is a particularly important issue because subjects
with chronic kidney disease may die before occurrence of renal failure (lung cancer,
hypertension, cardiac disease)]
Representativeness
Non-exposed subjects
Eligibility criteria
- was any subject or were subjects with possibly existing kidney damage
systematically excluded?
Selection procedure
Participation
Lost cases during follow-up [This is a particularly important issue because subjects
with chronic kidney disease may die before occurrence of renal failure (lung cancer,
hypertension, cardiac disease)]
Representativeness
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Summary of the constitution of the study population (Flow chart showing the successive
steps of the constitution of the study population with the reason for exclusion/drop outs at
each step) and assessment of the comparability of exposed and control subjects
11. Exposure
Exposure
Exposed subjects
-Occupational/environmental
-Time of exposure
-Changes of exposure with time
-Setting
-Type of Cd compound
Exposure duration:
Exposure intensity:
Personal protection equipment (PPE):
-Other substances present in the workplace (especially exposure to SiO2,
organic solvents, lead)
-Have acute Cd poisonings occurred in this setting?
-non exposed subjects
-how is the lack of exposure defined?
12. Exposure/Methodological aspects
Exposure assessment
-only qualitative (Itai-itai, tubular dysfunction)
-How was the diagnosis made (Diagnostic criteria, blind review, review by a
panel)
-air or blood or urine sampling
-collection, sampling, conservation
-contamination
-external quality control
-internal quality control
-can the authors prove that the results from the beginning of the study are
comparable with those of the end of the study?
-samples from exposed and unexposed collected simultaneously,
examined simultaneously, blind
-representative sampling
- when was sampling carried out (beginning or end of exposure, during
exposure, after exposure (in this case: how long after end of exposure?)
-how many samples during the follow up
-range in the reference group or the control group
-exposure reconstruction (method, blind, expert panel)
Summary about exposure (Intensity, duration frequency, probability)
13. Endpoint
-is the issue of changes of diagnostic criteria, treatment (introduction of dialysis,
transplantation, cyclosporin), and methods (proteinuria, clearance) approached?
-clinical effects
-clinical effect defined according to which clinical criteria (morbidity, mortality,
disease categories?
-what was the source of these criteria?
-was the diagnosis blind? Was there a review “panel”?
-source of information about the disease
-which information about reliability and about completeness?
-differential diagnosis: obstruction/reflux/stones; see population
-urinary sediment
-which method?
-samples from exposed and unexposed collected simultaneously,
examined simultaneously, blind
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-GFR
-inulin or other marker? If creatinine: which method?
-how many measurements and during which time period?
- was the time of sample collection for clearance/GFR assessment
standardized and the same in exposed and control subjects?
-relation with true creatinine, influence of chromogens, calibration
-can the authors prove that the results from the beginning of the study are
comparable with those of the end of the study?
-how was it estimated (inulin, creatinine clearance, etc.; during which time
period?)
-reference values (definition; number of subjects; mean, median, range,
percentiles); definition of pathological results (objective or arbitrary cut off)
If categories were defined what are these categories? How were they
defined?
-samples from exposed and unexposed collected simultaneously,
examined simultaneously, blind
-which statistical method has been applied (slope or threshold)
-how many determination over 3 months?
-linearity hypothesis
-was linearity only assumed or examined? How (statistical analysis
was
repeated with classes, linearity was tested, others methods)?
-reference values (definition; number of subjects; mean, median, range,
percentiles)
-quality control (internal, external, accuracy, precision)
-which unit (ml/mn; ml/mn/1.73m2); are they extremes values of weight?
-Proteinuria
-which method?
-how was calibration done (with serum protein, bovine albumin, etc.)
-Quality control (internal, external, accuracy, precision)
-urine collection (first or second morning urine, spot urine, middle stream, etc.)
-how many measurements and during which time period?
-reference values (definition; number of subjects; mean, median, range,
percentiles); definition of pathological results (objective or arbitrary cut off)
If categories were defined what are these categories? How were they
defined?
-limit of detection (especially important for tubulointerstitial diseases if the
method is devised to detect only clinically important proteinuria because weak
proteinurias are not detected)
-respective sensitivity to HMW and LMW proteins
-can the authors prove that the results from the beginning of the study are
comparable with those of the end of the study?
General
High molecular weight
Low molecular weigh
-samples from exposed and unexposed collected simultaneously,
examined simultaneously, blind
-Concentration ability
Which method?
-Radiological examinations
Which ones?
-Biopsy
Blind assessment? Assessment score? What was considered (glomerulus,
tubulus, interstitium, vasculature)?
14. Endpoint/Methodological aspects
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This information is summarized under Endpoints.
15. Interview
-explanation to the participants?
-blind?
-coding?
16. Biases
Prospective and historic prospective cohorts
Selection bias: see Selection
Performance bias
Detection bias
Preplacement medical examination
Periodic medical examination
Surveillance bias
Changes (for changes as to exposure: see under exposure, as to treatment:
see under study population, as to diagnostic criteria: see under endpoint)
Case control studies
Preplacement medical examination
Periodic medical examination
Changes (for changes as to exposure: see under exposure, as to treatment:
see under study population, as to diagnostic criteria: see under endpoint)
Recall bias
Exposure suspicion bias
Diagnosis suspicion bias (urogenital disease is attributed to urinary tract or to
kidney in the non exposed and exposed group, respectively)
Reporting bias (especially in regions where there have been numerous
studies
in the same population).
17. Confounding factors
Note: the main characteristics of the population are listed under “Population”.
Note: see under “Statistics” regarding multivariable analysis
Baseline GFR estimate
18. Causality criteria
Consistency
Is coherence well discussed?
Plausibility
Dose-effect (response) relationship
Specificity (identification of cadmium as the probable causal agent)
Strength
Temporality:
Exposure occurred before any kidney damage
Latency time
Experiment
Analogy
19. Main results
20. Short summary (population, selection, exposure, endpoint, results, comments)
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