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A Systematic Review of Renal Impairment and Use of Oral Sodium Phosphate as a Bowel Cleanser
Table 2: Characteristics and Results of the Epidemiological Studies
Author/Year/ Design Number Control and Pre-colonsocopy Outcome Main Results Risk Factors for
Country on OSP Numbers Renal Status Renal Injury
Abaskharoun, Retrospective cohort 618 PEG: 149 No exclusion criteria Abnormal creatinine or No increased risk Age and BP
2007, Canada of patients with two stated; two of 618 abnormal creatinine of chronic renal failure
colonoscopies on OSP had CRF clearance before from OSP
0.25–9 years apart second colonoscopy
between 0.25 and
9 years
Brunelli, Retrospective nested NA NA Creatinine ≤1.5mg/dl Creatinine ≥0.5mg/dl No increased risk of Female sex, CCF,
2007, US case control: 116 in preceding 6 months or 25% increase renal failure from OSP: diuretics
cases and 349 controls within 6 months OR 0.70 for OSP versus
other laxatives
Hurst, Retrospective cohort 6,432 PEG: 3,367 Creatinine measured AKI: serum creatinine OR 2.35, 95% CI Age
2007, US 12 months and values recorded within 1.51–3.66; p<0.001
<60ml/min/1.73m
2
365 days before and
were excluded after colonoscopy
Khurana, Retrospective cohort 286 No OSP: 125 Creatinine <1.5mg/dl GFR within 6 months Statistical difference of Baseline
2008, US with external control within 6 months GFR decline of 6ml/min/ creatinine level,
group 1.73m
2
with OSP diabetes, ACEI/ARB
Russman, Retrospective cohort 2,083 PEG: 269 No renal dysfunction GFR <60ml/min or Risk not increased: Age >65, previous
2007, US or GFR >60ml/min >10ml/min decrease or RR=1.13 GFR <90ml/min,
within 12 months two-fold increase in ACE-I, ARBs, diuretics,
creatinine within hypertension,
6 months African-American
race, low baseline GFR
Russman, Retrospective 126 PEG: 191 Renal dysfunction or Serum Cr increased Risk increased for OSP: None
2008, US GFR <60ml/min ≥0.5mg/dl within 14 RR=12
days of colonoscopy
Singal, Retrospective 157 PEG: 154 Creatinine ≤1.5mg/dl ≥50% increase in Minor increase in NSAID
2008, US chart review creatinine mean creatinine; ≥25%
increase; >50% increase
not significant
CRF = chronic renal failure; RR = relative risk; OR = odds ratio; CCF = congestive cardiac failure; BP = blood pressure; ACEI = angiotensin-converting enzyme inhibitor; ARB = angiotensin
receptor blocker; CI = confidence interval; OSP = oral sodium phosphate; GFR = glomerular filtration rate; NSAID = non-steoidal anti-inflammatory drug; AKI = acute kidney injury.
Case Reports and Case Series Randomised Controlled Trials
We identified a total of 103 cases. Data from four reports were The randomised controlled trial is the most valid design to answer
missing, so we had data from 99 patients (see Table 3), of whom cause and effect questions. There were no renal events recorded in a
47% were 65 years of age or older, 62.5% were female, 59% had total of 32 studies involving a total of 6,580 patients. This may be
hypertension, diabetes or both and 20% had a previous history of because the incidence of renal events is rare, and much lower than
chronic renal failure; in 15% of the cases, doses of OSP above those the figures of 1.2%
62
and 0.3%
22
quoted in published case series. If the
recommended in the data sheet were identified. Acute renal failure incidence of a renal event were 0.1%, with 3,000 patients exposed to
developed in 56%, mostly diagnosed with the newly coined term OSP there would have been a 95% chance of observing at least one
acute phosphate nephropathy; 6% were cases of life-threatening renal event and an 80% chance of observing at least two renal events.
severity and 2% of cases ended in death. Only 8.8% of cases, where An absence of renal events may also have arisen because the
country was stated, emanated from Europe. recommendations in the data sheet for OSP were closely followed,
with adequate patient selection and compliance. All of the patients in
Data from the CB Fleet Company Database the North American studies were prescribed OSP by the physician.
The reporting rate of serious renal impairment for Phospho-soda in Thus, when recommendations are followed, the risk of renal events
the Fleet company database in 2007 and 2008 in Europe was 2.9 may be reduced.
and 6.03 per million units sold, respectively. Table 4 shows the
number of medically confirmed serious adverse events (SAEs) Epidemiological Studies
reported to the company for the EU countries for 2007 and 2008 Epidemiological cohort and case-control studies are the next most
and for the first quarter of 2009. Table 5 shows the SAE rates for EU valid designs to evaluate cause and effect questions. Unfortunately,
medically confirmed cases. All of the rates fall below the one in the results from the different studies were mixed. This varying picture
10,000 threshold used to define an event as ‘very rare’. may have occurred in part due to the different study designs,
including inclusion/exclusion criteria, definitions of renal injury and
Discussion pre- and post-procedure time intervals.
The results from the different study designs are very different. An
amalgamation of the evidence is required with appropriate When pre-existing renal dysfunction was excluded, OSP exposure
considerations for the biases in each type of study design. was not associated with kidney injury or clinically significant
EUROPEAN GASTROENTEROLOGY & HEPATOLOGY REVIEW 17
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