End-stage renal disease and non-narcotic analgesics: a case-control study

Information and consensus document for the detection and management of chronic kidney disease

Chronic kidney disease (CKD) is a major public health problem worldwide that affects more than 10% of the Spanish population. CKD is associated with high comorbidity rates, poor prognosis and major consumption of health system resources. Since the publication of the last consensus document on CKD seven years ago, little evidence has emerged and few clinical trials on new diagnostic and treatment strategies in CKD have been conducted, apart from new trials in diabetic kidney disease. Therefore, CKD international guidelines have not been recently updated. The rigidity and conservative attitude of the guidelines should not prevent the publication of updates in knowledge about certain matters that may be key in detecting CKD and managing patients with this disease. This document, also prepared by 10 scientific associations, provides an update on concepts, clarifications, diagnostic criteria, remission strategies and new treatment options. The evidence and the main studies published on these aspects of CKD have been reviewed. This should be considered more as an information document on CKD. It includes an update on CKD detection, risk factors and screening; a definition of renal progression; an update of remission criteria with new suggestions in the older population; CKD monitoring and prevention strategies; management of associated comorbidities, particularly in diabetes mellitus; roles of the Primary Care physician in CKD management; and what not to do in Nephrology. The aim of the document is to serve as an aid in the multidisciplinary management of the patient with CKD based on current recommendations and knowledge.

Assessment of Prescription Analgesic Use in Older Adults With and Without Chronic Kidney Disease and Outcomes

IMPORTANCE

Pain is a common symptom among patients with kidney disease. However, little is known about use of analgesics among patients aged 65 years or older with chronic kidney disease (CKD) who do not receive dialysis treatment.

OBJECTIVE

To assess national trends and geographic variations in use of opioids and prescription nonsteroidal anti-inflammatory drugs (NSAIDs) in older adults with and without CKD in the US (2006-2015) and examine associations between use of opioids and patient outcomes.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study used the 5% Medicare claims data (2005-2015) to select 10 retrospective annual cohorts of Medicare Part D beneficiaries aged 65 years and older from 2006 to 2015 and a retrospective longitudinal cohort. Data were analyzed in August 2019.

EXPOSURES

CKD status and other comorbidities identified using International Classification of Diseases, Ninth Revision, Clinical Modification codes.

MAIN OUTCOMES AND MEASURES

Analgesic use was measured by overall use (proportion of ever used opioids/NSAIDs), long-term use (prescribed >90 days), and cumulative use (total annual days' supply). Patient outcomes included progression to end-stage kidney disease (ESKD) and all-cause mortality.

RESULTS

A total of 6 260 454 beneficiaries (9.6% identified with CKD by claims) were selected in the annual cohorts and 649 339 beneficiaries (8.3% identified with CKD) were selected in the longitudinal cohort. There was significant growth in opioid use (31.2%-42.4%) and NSAID use (10.7%-16.6%) among patients aged 65 years and older with CKD from 2006 to 2015. Long-term use of opioids increased during 2006 to 2014 (25.8%-36.7%) but decreased through 2015 at 35.6%, while long-term use of NSAIDs remained stable. Opioid use was higher in patients with CKD, particularly CKD stages 4 to 5 (odds ratio [OR], 1.35; 95% CI, 1.33-1.37; P < .001) compared with non-CKD. NSAID use was lower in patients with CKD stages 4 to 5 (OR, 0.55; 95% CI, 0.54-0.56; P < .001). Substantial geographic variations in analgesic use were observed across states (opioid use in CKD: 24.7%-54.3%; NSAID use in CKD: 11.2%-20.8%, 2012-2015). Opioid use was associated with progression to ESKD (hazard ratio [HR], 1.10; 95% CI, 1.04-1.16; P = .001) and death (HR, 1.19; 95% CI, 1.18-1.20; P < .001) independent of CKD status and other covariates. There was an inverse association between NSAID use and death (HR, 0.84; 95% CI, 0.83-0.85; P < .001).

CONCLUSIONS AND RELEVANCE

Among Medicare patients with CKD, use of prescription analgesics, both opioid and NSAID, increased from 2006 to 2015. Optimizing pain management in a complex condition such as kidney disease should remain a priority for clinicians and researchers alike.

Pros and Cons of Aspirin Prophylaxis for Prevention of Cardiovascular Events in Kidney Transplantation and Review of Evidence

Kidney transplant recipients have traditional and nontraditional risk factors which can lead to coronary artery disease and sudden death with a functional graft loss. Aspirin has been used traditionally for prevention of cardiovascular and cerebrovascular accidents. It has beneficial effects in secondary prevention of cardiovascular events in general population. Its use for primary prophylaxis is still disputed. Bleeding and theoretical risk of nephrotoxicity are the major concerns about its use. The data on aspirin in kidney transplant population is sparse. This review will focus on various pros and cons of aspirin use for prevention of cardiovascular events in kidney transplant recipients and a way forward.

Is Long-Term Low-Dose Aspirin Therapy Associated with Renal Dysfunction in Patients with Type 2 Diabetes? JPAD2 Cohort Study

Background

Low-dose aspirin is widely recommended for patients at high risk for cardiovascular disease (CVD); however, it remains uncertain whether long-term treatment adversely affects renal function in patients with diabetes.

We investigated whether long-term low-dose aspirin affects renal dysfunction in patients with diabetes.

Methods

We conducted a randomized controlled trial (RCT), the Japanese Primary Prevention of Atherosclerosis with Aspirin for Diabetes (JPAD) trial, to evaluate low-dose aspirin as primary prevention for CVD in patients with type 2 diabetes. We followed the patients with negative urine dipstick albumin of the JPAD trial in a cohort study after the RCT period was completed. Patients were randomly allocated to receive aspirin (81 mg or 100 mg daily, aspirin group) or no aspirin (no aspirin group). After the RCT, the treating physician decided whether to administer aspirin. We evaluated the incidence of positive urine dipstick albumin and annual changes in estimated glomerular filtration rate (eGFR).

Results

Positive urine dipstick albumin developed in 297 patients in the aspirin group (n = 1,075) and 270 patients in the no aspirin group (n = 1,098) during follow-up (median, 8.5 years). Intention-to-treat analysis showed low-dose aspirin did not increase the incidence of positive urine dipstick albumin (hazard ratio [HR], 1.17; 95% confidence interval [CI], 0.995–1.38). On-treatment analysis yielded similar results (HR, 1.08; 95% CI, 0.92–1.28). Multivariable analysis showed the incidence of positive urine dipstick albumin was higher among the elderly and those with elevated serum creatinine, high hemoglobin A1c, or high blood pressure; however, low-dose aspirin did not increase the risk of positive urine dipstick albumin. There were no significant differences in annual changes in eGFR between the groups (aspirin, −0.8 ± 2.9; no aspirin, −0.9 ± 2.5 ml/min/1.73m²/year).

Conclusion

Long-term low-dose aspirin does not affect eGFR and positive urine dipstick albumin in patients with type 2 diabetes.

Evaluating ethnic differences in the prescription of NSAIDs for chronic kidney disease: a cross-sectional survey of patients in general practice

BACKGROUND

The public health burden of chronic kidney disease (CKD) and end-stage kidney disease is a national priority and is the subject of recent guidelines. In the UK, ethnic minority groups are over-represented in the renal replacement population (17.8%) compared with the white population (11%).

AIM

Non-steroidal anti-inflammatory drugs (NSAIDs) are a preventable cause of renal damage. Previous studies suggest a prescribing prevalence between 9% and 36% among those with CKD, but have not examined differences by ethnic group.

DESIGN AND SETTING

Cross-sectional survey of 12 011 patients with identified CKD (stages 3-5) in the three PCTs of Tower Hamlets, Hackney, and Newham.

METHOD

Assessment of NSAID prescribing rates in a multi-ethnic, socially-deprived population, using descriptive and multivariate analysis.

RESULTS

NSAIDs were prescribed for 11.1% of patients with CKD in the year prior to November 2012. Prescribing rates decreased stepwise by stage of renal impairment. Using daily defined dosages this study shows that in comparison with white groups both South Asian and black groups are much less likely to be in the top decile of NSAID prescribing, hence the overall prescribing load will be less: (odds ratio [OR] for South Asians = 0.34, 95% confidence interval [CI] = 0.22 to 0.54, OR for black groups = 0.34, 95% CI = 0.19 to 0.63).

CONCLUSION

National rates of NSAID prescribing continue to rise, and over-the-counter sales remain unmonitored, despite longstanding concerns about renal outcomes. Prescribing patterns indicate that GPs reduce prescribing as CKD progresses. Differential use of NSAIDs by ethnic group is unlikely to contribute to the high rates of end-stage kidney disease in ethnic minority groups.

Causes of end stage renal failure among haemodialysis patients in Khartoum State/Sudan

Background

End stage renal failure (ESRF) has become a major health problem in Sub Saharan Africa (SSA). There were limited data about causes of ESRF in the Sudan.

Methods

This is a cross sectional hospital based descriptive study. The subjects of the study are ESRF adults’ patients on regular haemodialysis treatment in 15 haemdoialysis centres in Khartoum State—Sudan. Clinical and epidemiological data were obtained from 1583 patients. The medical files of each patient were reviewed to identify the cause of ESRF. Concerning the causes of ESRF, diabetes was diagnosed based on the past medical history and result of the glucose tolerance test, hypertension was diagnosed based on past history of hypertension based on blood pressure of more than 140/90 mmHg, glomerulonephritis was diagnosed based on results of previous kidney biopsies and on clinical grounds, polycystic kidney disease and obstructive uropathy were diagnosed based on abdominal ultrasound and other imaging modalities, sickle cell anaemia was diagnosed based on the result of haemoglobin electrophoresis, systemic lupus erythematosus was diagnosed based on the clinical criteria in addition to lab results of auto antibodies, and analgesic nephropathy was diagnosed based on past medical history of chronic analgesic drugs usage with no other identifiable risk factors. We included all ESRF patients on regular haemodialysis treatment. We excluded ESRF patients less than 18 years old.

Results

The results showed that the mean age of ESRF Patients was 49 ± 15.8 (years) and 63.4 % were male and 76.3 % were unemployed. The mean duration of haemodialysis is 4.38 ± 4.24 (years). The most common cause of ESRF in our patients was hypertension (34.6 %) followed by chronic glomerulonephritis (17.6 %), diabetes mellitus (12.8 %), obstructive uropathy (9.6 %), autosomal dominant poly cystic kidney disease (ADPKD) (4.7 %), chronic pyelonephritis (4.6 %), analgesic nephropathy (3.5 %). However in (10.7 %) no cause was found. In patient aged less than 40 years old the leading cause of ESRF was glomerulonephritis (29.3 %) followed by hypertension (25 %). In patient aged between 40 to 60 years old the leading cause of ESRF was hypertension (38.5 %) followed by diabetes mellitus (14 %). In patient aged older than 60 years the leading cause of ESRF was hypertension (38.4 %) followed by diabetes mellitus (23.3 %).

Conclusions

ESRF in Sudan affects the economically productive age group; unemployment rate among ESRF patients is high. The study showed that hypertension is a leading cause of ESRF in Sudan followed by chronic glomerulonephritis. Hypertension and diabetes mellitus are the leading causes of ESRF among patients over 40 years old.

[Consensus document for the detection and management of chronic kidney disease]

La enfermedad renal crónica (ERC) es un importante problema de salud pública que puede afectar en sus diferentes estadios a cerca del 10% de la población española y que supone una elevada morbimortalidad, así como un importante consumo de recursos al Sistema Nacional de Salud. Diez sociedades científicas involucradas en el manejo del paciente renal nos hemos puesto de acuerdo para hacer una puesta al día del anterior documento de consenso sobre ERC de 2007. El presente es la edición abreviada del documento general extenso, que puede ser consultado en las páginas Web de cada una de las sociedades firmantes. Contiene los siguientes aspectos: definición, epidemiología y factores de riesgo de la ERC; criterios de diagnóstico, evaluación y estadificación de la ERC, albuminuria y estimación del filtrado glomerular; concepto y factores de progresión; criterios de derivación a nefrología; seguimiento del paciente, actitudes y objetivos por especialidad; prevención de la nefrotoxicidad; detección del daño cardiovascular; actitudes, estilo de vida y tratamiento: manejo de la hipertensión arterial, dislipidemia, hiperglucemia, tabaquismo, obesidad, hiperuricemia, anemia, alteraciones del metabolismo mineral y óseo; seguimiento coordinado por atención primaria-otras especialidades-nefrología; manejo del paciente en tratamiento renal sustitutivo, hemodiálisis, diálisis peritoneal y trasplante renal; tratamiento paliativo de la uremia terminal. Esperamos que sirva de gran ayuda en el manejo multidisciplinar del paciente con ERC, a la vista de las recomendaciones más actualizadas.

[Consensus document for the detection and management of chronic kidney disease]

Chronic kidney disease (CKD) is an important global health problem, involving to 10% of the Spanish population, promoting high morbidity and mortality for the patient and an elevate consumption of the total health resources for the National Health System. This is a summary of an executive consensus document of ten scientific societies involved in the care of the renal patient, that actualizes the consensus document published in 2007. The central extended document can be consulted in the web page of each society. The aspects included in the document are: Concept, epidemiology and risk factors for CKD. Diagnostic criteria, evaluation and stages of CKD, albuminuria and glomerular filtration rate estimation. Progression factors for renal damage. Patient remission criteria. Follow-up and objectives of each speciality control. Nephrotoxicity prevention. Cardio-vascular damage detection. Diet, life-style and treatment attitudes: hypertension, dyslipidaemia, hyperglycemia, smoking, obesity, hyperuricemia, anemia, mineral and bone disorders. Multidisciplinary management for Primary Care, other specialities and Nephrology. Integrated management of CKD patient in haemodialysis, peritoneal dialysis and renal transplant patients. Management of the uremic patient in palliative care. We hope that this document may be of help for the multidisciplinary management of CKD patients by summarizing the most updated recommendations.

Non-steroidal anti-inflammatory drugs and chronic kidney disease progression: a systematic review

BACKGROUND

Non-steroidal anti-inflammatory drugs (NSAIDs) are widely regarded as one risk factor, which influences chronic kidney disease (CKD) progression. However, previous literature reviews have not quantified the risk in moderate to severe CKD patients.

OBJECTIVE

To estimate the strength of association between chronic NSAID use and CKD progression.

METHODS

We conducted a systematic review and meta-analysis of observational general practice or population studies featuring patients aged 45 years and over. The electronic databases searched were MEDLINE, EMBASE, Cochrane, AMED, BNI and CINAHL until September 2011 without date or language restrictions. Searches included the reference lists of relevant identified studies, WEB of KNOWLEDGE, openSIGLE, specific journals, the British Library and expert networks. For relevant studies, random effects meta-analysis was used to estimate the association between NSAID use and accelerated CKD progression (estimated glomerular filtration rate decline ≥ 15 ml/min/1.73 m2).

RESULTS

From a possible 768 articles, after screening and selection, seven studies were identified (5 cohort, 1 case-control and 1 cross-sectional) and three were included in the meta-analysis. Regular-dose NSAID use did not significantly affect the risk of accelerated CKD progression; pooled odds ratio (OR) = 0.96 (95%CI: 0.86-1.07), but high-dose NSAID use significantly increased the risk of accelerated CKD progression; pooled OR = 1.26 (95%CI: 1.06-1.50).

CONCLUSIONS

The avoidance of NSAIDs in the medium term is unnecessary in patients with moderate to severe CKD, if not otherwise contraindicated. As the definition of high-dose of NSAID use remains unclear, the lowest effective dose of NSAIDs should be prescribed where indicated.

Analgesic use and the risk for progression of chronic kidney disease

PURPOSE

The chronic effect of various analgesics on the progression of chronic kidney disease (CKD) is inconclusive. There is also lack of information on the renal safety of selective cyclooxygenase-2 (COX-2) inhibitors. This study aimed to clarify the renal risk of analgesic use in CKD patients.

METHODS

A cohort study using a nationally representative database randomly sampled from National Health Insurance (NHI) enrollees was performed. The study population included a total of 19,163 newly diagnosed CKD patients. Clinical conditions were defined by diagnostic codes and exposure information on analgesics was derived from service claims. Cox proportional hazard model was used to assess the association between analgesic use and the risk of progression to end stage renal disease (ESRD).

RESULTS

CKD patients using acetaminophen, aspirin, and non-selective non-steroidal anti-inflammatory drugs (NSAIDs) had an increased risk for ESRD with multivariable-adjusted HRs (95%CIs) of 2.92 (2.47-3.45), 1.96 (1.62-2.36), and 1.56 (1.32-1.85), respectively. The trends toward higher risk with increasing exposure dose were significant for all classes of analgesics (all P for trend < 0.001). Among COX-2 inhibitors, only rofecoxib, but not celecoxib, shows a significant risk association with ESRD (HR = 1.98; 95%CI, 1.15-3.40).

CONCLUSIONS

Our data indicated exacerbating effects of acetaminophen, aspirin, and non-selective NSAIDs on CKD in a dose-dependent manner. For COX-2 inhibitors, only rofecoxib showed an increased risk for ESRD. Although the possibility of residual confounding cannot be completely ruled out, given the common use of analgesics, the possible relation suggested by this study warrants further investigation.

Nonsteroidal Anti-Inflammatory Drugs and the Kidney

Non-steroidal anti-inflammatory drugs (NSAIDs) inhibit the isoenzymes COX-1 and COX-2 of cyclooxygenase (COX). Renal side effects (e.g., kidney function, fluid and urinary electrolyte excretion) vary with the extent of COX-2-COX-1 selectivity and the administered dose of these compounds. While young healthy subjects will rarely experience adverse renal effects with the use of NSAIDs, elderly patients and those with co-morbibity (e.g., congestive heart failure, liver cirrhosis or chronic kidney disease) and drug combinations (e.g., renin-angiotensin blockers, diuretics plus NSAIDs) may develop acute renal failure. This review summarizes our present knowledge how traditional NSAIDs and selective COX-2 inhibitors may affect the kidney under various experimental and clinical conditions, and how these drugs may influence renal inflammation, water transport, sodium and potassium balance and how renal dysfunction or hypertension may result.

ISFM and AAFP Consensus Guidelines: Long-Term use of NSAIDs in Cats

NSAIDs and cats Non-steroidal anti-inflammatory drugs (NSAIDs) are an important class of drug in feline medicine, having analgesic, anti-inflammatory and antipyretic activity. While most published data on their use in this species relate to short-term (often perioperative) therapy, there is increasing evidence of the value of these drugs in treating chronic pain in cats (for example, that associated with degenerative joint disease), and some NSAIDs have now become licensed for long-term use in cats in some geographies. Most of our knowledge of therapeutic mechanisms or adverse drug reactions associated with NSAIDs is extrapolated from work in other species, and there is a paucity of published data relating to cats.

Guidelines These guidelines have been drawn together by an expert panel, which have reviewed the current literature on long-term NSAID use in cats and other species, and developed guidance on their use based on this information. The aim is to provide practical information for veterinarians to encourage appropriate NSAID therapy whenever cats will benefit from the use of these drugs.

End-stage renal disease in Taiwan: a case-control study

Background

Taiwan has the highest incidence of end-stage renal disease (ESRD) in the world. The epidemiologic features of ESRD, however, have not been investigated. In this case–control study, we evaluated the risk of ESRD associated with a number of putative risk factors.

Methods

We studied 200 patients among whom ESRD had been newly diagnosed between 1 January 2005 and 31 December 2005; 200 controls were selected from among relatives of patients treated in the general surgery unit. Using a structured questionnaire, we collected information related to socioeconomic factors, history of disease, regular blood or urine screening, lifestyle, environmental exposure, consumption of vitamin supplements, and regular drug use at 5 years before disease onset.

Results

Our primary multivariate risk models indicated that low socioeconomic status was a strong predictor of ESRD (education: odds ratio [OR], 2.78; 95% confidence interval [CI], 1.49–5.19; income: OR, 2.86, 95% CI, 1.48–5.52), even after adjusting for other risk factors. Other significant predictors for ESRD were a history of hypertension (OR, 3.63–3.90), history of diabetes (OR, 3.85–5.50), and regular intake of folk remedies or over-the-counter Chinese herbs (OR, 10.84–12.51). Regular intake of a multivitamin supplement 5 years before diagnosis was associated with a decreased risk of ESRD (OR, 0.12–0.14).

Conclusions

Our findings indicate that low socioeconomic status, history of hypertension, diabetes, and regular use of folk remedies or over-the-counter Chinese herbs were significant risk factors for ESRD, while regular intake of a multivitamin supplement was associated with a decreased risk of ESRD.

Over-the-counter analgesic use

Chronic analgesic nephropathy, particularly chronic interstitial nephritis and renal papillary necrosis, results from daily use for many years of mixtures containing at least two analgesics and caffeine or dependence-inducing drugs. Computed tomography scan can accurately diagnose this disease even in the absence of reliable information on previous analgesic use. The occasion to moderate regular use of aspirin and nonsteroidal anti-inflammatory drugs is without renal risk when renal function is normal. Paracetamol use is less clear although the risk is not great. The continued use of non-phenacetin-combined analgesics with or without nonsteroidal anti-inflammatory drugs is associated with faster progression toward renal impairment. As long as high-risk analgesic mixtures are available over the counter, analgesic nephropathy will continue to be a problem.

Acetaminophen, aspirin and progression of advanced chronic kidney disease

BACKGROUND

Although many studies have investigated the possible association between analgesic use (acetaminophen and aspirin) and the development of chronic kidney disease (CKD), the effect of analgesics on the progression of established CKD of any cause has not yet been investigated.

METHODS

In this population-based Swedish cohort study, we investigated the decline over 5-7 years in estimated glomerular filtration rate (eGFR) among 801 patients with incident, advanced CKD (serum creatinine >3.4 mg/dL for men, >2.8 mg/dL for women for the first time) and with different analgesic exposures. Lifetime analgesic use and current regular use were ascertained through in-person interviews at inclusion while data on analgesic use during the follow-up was abstracted from the medical records at the end of the study period. A linear regression slope, based on their eGFR values during the follow-up, provided a summary of within-individual change. In the final multivariate analyses, a linear mixed effects model was implemented to assess the relation of analgesic use and change in eGFR over time.

RESULTS

The progression rate for regular users of acetaminophen was slower than that for non-regular users (regular users progressed 0.93 mL/min/1.73 m(2) per year slower than non-regular users; 95% CI 0.03, 1.8). For regular users of aspirin, the progression rate was significantly slower than that for non-regular users (regular users progressed 0.80 mL/min/1.73 m(2) per year slower than non-regular users; 95% CI 0.1, 1.5). Different levels of lifetime cumulative dose of acetaminophen and aspirin did not significantly affect the progression rate.

CONCLUSION

We suggest that single substance acetaminophen and aspirin may be safe to use by patients with diagnosed advanced CKD stage 4-5 without an adverse effect on the progression rate of the disease.

Analgesics use and ESRD in younger age: a case-control study

BACKGROUND

An ad hoc peer-review committee was jointly appointed by Drug Authorities and Industry in Germany, Austria and Switzerland in 1999/2000 to review the evidence for a causal relation between phenacetin-free analgesics and nephropathy. The committee found the evidence as inconclusive and requested a new case-control study of adequate design.

METHODS

We performed a population-based case-control study with incident cases of end-stage renal disease (ESRD) under the age of 50 years and four age and sex-matched neighborhood controls in 170 dialysis centers (153 in Germany, and 17 in Austria) from January 1, 2001 to December 31, 2004. Data on lifetime medical history, risk factors, treatment, job exposure and intake of analgesics were obtained in a standardized face-to-face interview using memory aids to enhance accuracy. Study design, study performance, analysis plan, and study report were approved by an independent international advisory committee and by the Drug Authorities involved. Unconditional logistic regression analyses were performed.

RESULTS

The analysis included 907 cases and 3,622 controls who had never used phenacetin-containing analgesics in their lifetime. The use of high cumulative lifetime dose (3rd tertile) of analgesics in the period up to five years before dialysis was not associated with later ESRD. Adjusted odds ratios with 95% confidence intervals were 0.8 (0.7 - 1.0) and 1.0 (0.8 - 1.3) for ever- compared with no or low use and high use compared with low use, respectively. The same results were found for all analgesics and for mono-, and combination preparations with and without caffeine. No increased risk was shown in analyses stratifying for dose and duration. Dose-response analyses showed that analgesic use was not associated with an increased risk for ESRD up to 3.5 kg cumulative lifetime dose (98 % of the cases with ESRD). While the large subgroup of users with a lifetime dose up to 0.5 kg (278 cases and 1365 controls) showed a significantly decreased risk, a tiny subgroup of extreme users with over 3.5 kg lifetime use (19 cases and 11 controls) showed a significant risk increase. The detailed evaluation of 22 cases and 19 controls with over 2.5 kg lifetime use recommended by the regulatory advisors showed an impressive excess of other conditions than analgesics triggering the evolution of ESRD in cases compared with controls.

CONCLUSION

We found no clinically meaningful evidence for an increased risk of ESRD associated with use of phenacetin-free analgesics in single or combined formulation. The apparent risk increase shown in a small subgroup with extreme lifetime dose of analgesics is most likely an indirect, non-causal association. This hypothesis, however, cannot be confirmed or refuted within our case-control study. Overall, our results lend support to the mounting evidence that phenacetin-free analgesics do not induce ESRD and that the notion of "analgesic nephropathy" needs to be re-evaluated.

NSAID use and progression of chronic kidney disease

PURPOSE

The effects of nonselective and selective cyclooxygenase-2 specific (COX-2) nonsteroidal anti-inflammatory drug (NSAID) use on the progression of chronic kidney disease (CKD) is uncertain. Due to the high prevalence of both CKD and NSAID use in older adults, we sought to determine the association between NSAID use and the progression of CKD in an elderly community-based cohort.

METHODS

All subjects > or =66 years of age who had at least one serum creatinine measurement in 2 time periods (July-December, 2001 and July-December, 2003) were included. Multiple logistic regression analyses, including covariates for age, sex, baseline estimated glomerular filtration rate (eGFR), diabetes, and comorbidity were used to explore the associations of NSAID use on the primary (decrease in eGFR of > or =15 mL/min/1.73) and secondary (mean change in eGFR) outcomes.

RESULTS

A total of 10,184 subjects (mean age 76 years; 57% female) were followed for a median of 2.75 years. High-dose NSAID users (upper decile of cumulative NSAID exposure) experienced a 26% increased risk for the primary outcome (odds ratio [OR] 1.26, 95% confidence interval [CI], 1.04-1.53). A linear association between cumulative NSAID dose and change in mean GFR also was seen. No risk differential was identified between selective and nonselective NSAID users.

CONCLUSIONS

High cumulative NSAID exposure is associated with an increased risk for rapid CKD progression in the setting of a community-based elderly population. For older adult patients with CKD, these results suggest that nonselective NSAIDs and selective COX-2 inhibitors should be used cautiously and chronic exposure to any NSAID should be avoided.

Use of analgesics and nonsteroidal anti-inflammatory drugs, genetic predisposition, and bladder cancer risk in Spain

BACKGROUND

We assessed use of nonaspirin nonsteroidal anti-inflammatory drugs (NSAID), aspirin, paracetamol (acetaminophen), phenacetin, and metamizol (dipyrone) and risk of bladder cancer and their interaction with polymorphisms in drug-metabolizing genes.

METHODS

We analyzed personal interview data from 958 incident bladder cancer cases and 1,029 hospital controls from a multicenter case-control study in Spain. A drug matrix was developed to estimate cumulative lifetime dose of active ingredients. Polymorphisms in GSTP1, SULT1A1, CYP2E1, CYP2C9, and NAT2 were examined.

RESULTS

A significant reduction in bladder cancer risk [adjusted odds ratio (OR), 0.4; 95% confidence interval (95% CI), 0.2-0.9] was observed for regular users of nonaspirin NSAIDs compared with never users. Regular users of aspirin experienced no reduction in risk (OR, 1.0; 95% CI, 0.7-1.5). Regular users of paracetamol had no overall increased risk of bladder cancer (OR, 0.8; 95% CI, 0.4-1.3), but our data suggested a qualitative interaction with the GSTP1 I105V genotype. Subjects with at least one copy of the 359L or 144C variant alleles in the NSAID-metabolizing gene CYP2C9 had a slightly decreased risk of bladder cancer (OR, 0.8; 95% CI, 0.7-1.0; P = 0.037); however, having at least one copy of the 359L or 144C variant alleles did not significantly modify the protective effect of nonaspirin NSAID use.

CONCLUSION

Regular use of nonaspirin NSAIDs was associated with a reduced risk of bladder cancer, which was not modified by polymorphisms in the NSAID-metabolizing gene CYP2C9. We found no evidence of an overall effect for paracetamol or aspirin use.

Nonnarcotic analgesics and hypertension

In 2004, individuals in the United States spent >$2.5 billion on over-the-counter (OTC) nonsteroidal anti-inflammatory drugs (NSAIDs) and filled >100 million NSAID prescriptions. The most commonly used OTC analgesics include aspirin, acetaminophen, and nonaspirin NSAIDs. Nonnarcotic analgesics are generally considered safe when used as directed but do have the potential to increase blood pressure in patients with hypertension treated with antihypertensives. This is important because hypertension alone has been correlated with an increased risk of cardiovascular disease or stroke. Small increases in blood pressure in patients with hypertension also have been shown to increase cardiovascular morbidity and mortality. Therefore, when nonnarcotic analgesics are taken by patients with hypertension, there may be important implications. This review explores the potential connection among analgesic agents, blood pressure, and hypertension, and discusses possible mechanisms by which analgesics might cause increases in blood pressure. This is followed by a summary of data on the relation between analgesics and blood pressure from both observational and randomized trials.

[Use of analgesics and aspirin in a Spanish multicenter study]

OBJECTIVE

To evaluate the use of acetaminophen (paracetamol), aspirin and dipyrone (metamizol) in a multicenter study.

PATIENTS AND METHOD

We analyzed the controls of a hospital-based case-control study (n = 1029) of bladder cancer using a matrix of drugs and active principles. The admission diagnosis of the study controls was not associated with chronic analgesic use. A logistic regression model was used.

RESULTS

Eight percent of the controls were regular users of aspirin, 5% regularly used acetaminophen and 2% regularly used dipyrone. Aspirin was more frequently used by subjects with at least secondary education (OR = 2.0; 95% CI, 1.52-2.93). Women more frequently used acetaminophen (OR = 1.91; 95% CI, 1.30-2.80) and dipyrone (OR = 2.80; 95% CI, 1.49-4.47). Subjects under 65 years old more frequently used dipyrone.

CONCLUSION

Chronic use of aspirin and acetaminophen is lower than that reported in North America or northern Europe and is similar to that seen in southern Europe. Differences in the pattern of analgesic use were found among sociodemographic population groups.

Case-control study of regular analgesic and nonsteroidal anti-inflammatory use and end-stage renal disease

BACKGROUND

Studies on the association between the long-term use of aspirin and other analgesic and nonsteroidal anti-inflammatory drugs (NSAIDs) and end-stage renal disease (ESRD) have given conflicting results. In order to examine this association, a case-control study with incident cases of ESRD was carried out.

METHODS

The cases were all patients entering the local dialysis program because of ESRD in the study area between June 1, 1995 and November 30, 1997. They were classified according to the underlying disease, which had presumably led them to ESRD. Controls were patients admitted to the same hospitals from where the cases arose, also matched by age and sex. Odds ratios were calculated using a conditional logistic model, including potential confounding factors, both for the whole study population and for the various underlying diseases.

RESULTS

Five hundred and eighty-three cases and 1190 controls were included in the analysis. Long-term use of any analgesic was associated with an overall odds ratio of 1.22 (95% CI, 0.89-1.66). For specific groups of drugs, the risks were 1.56 (1.05-2.30) for aspirin, 1.03 (0.60-1.76) for pyrazolones, 0.80 (0.39-1.63) for paracetamol, and 0.94 (0.57-1.56) for nonaspirin NSAIDs. The risk of ESRD associated with aspirin was related to the cumulated dose and duration of use, and it was particularly high among the subset of patients with vascular nephropathy as underlying disease [2.35 (1.17-4.72)].

CONCLUSION

Our data indicate that long-term use of nonaspirin analgesic drugs and NSAIDs is not associated with an increased risk of ESRD. However, the chronic use of aspirin may increase the risk of ESRD.

Case-control study on analgesics and nephropathy (SAN): protocol

Background

The association between intake of non-phenacetin-containing analgesics and the occurrence of chronic renal failure is still controversially discussed. A new epidemiologic study was planned and conducted in Germany and Austria.

Methods/design

The objective of the international, multicenter case-control study was to evaluate the association between end-stage renal disease (ESRD) and use of non-phenacetin-containing analgesics with particular emphasis on combined formulations. A targeted sample of 1000 new (incident) dialysis patients, aged less than 50 years, was planned to recruit between January 1, 2001 and December 31, 2004. The age limit was chosen to avoid contamination of the study population with phenacetin-containing analgesics to the extent possible. Four control subjects per ESRD case, matched by age, sex, and region were selected from the population living in the region the case came from.

Lifetime exposure to analgesics and potential renal risk factors were recorded in a single face-to-face interview. A set of aids was introduced to reinforce the memory of study participants.

A standardized, pre-tested interview questionnaire (participants), a medical documentation sheet (physicians in dialysis centres), a logbook for all activities (dialysis centres) were used to collect the necessary data.

Quality management consisted of the standardized procedures, (re-) training and supervision of interviewers, regular checks of all incoming data for completeness and plausibility.

The study is scientifically independent and governed by a international Scientific Advisory Committee that bridged the gap between the sponsoring companies and the investigators. Also other advisory groups assisted the managing committee of the study. All relevant German and Austrian nephrological associations supported the study, and the study design was carefully reviewed and approved by the Kidney Foundation of Germany.

Discussion

The study is expected to answer the main research question by end 2005. There is however a high potential for various biases that we tried to address with adequate measure. One limitation however cannot be overcome: The methodologically needed age-limitation of the study will make it not easy to generalize the results to age groups over 50 years. It might be suggested to repeat the study for persons over 50 years in 10 years when contamination with phenacetin use early in life is likely to be outgrown.

Treatment of pain in patients with renal insufficiency: The World Health Organization three-step ladder adapted

The World Health Organization established official recommendations for managing pain in cancer patients. Since then, this stepladder approach has been widely adopted as a conceptual framework to treat all types of pain. However, those guidelines have not been critically evaluated for use in patients with renal insufficiency. In these patients, the questions of drug dosage adjustment and renal toxicity must be considered. This article reviews the pharmacokinetics of major analgesic drugs and data on their use and/or behavior in renal failure and considers their potential nephrotoxicity. Finally, according to available data in the international literature on pharmacokinetics, recommendations for dosage adjustment in patients with renal failure, and their potential nephrotoxicity, the World Health Organization three-step ladder for the treatment of pain was modified and adapted for patients with impaired renal function. Perspective This well-known treatment strategy now adapted for use in patients with renal insufficiency should secure and rationalize pain treatment in those patients.

Chronic kidney disease: the global challenge

The worldwide rise in the number of patients with chronic kidney disease (CKD) and consequent end-stage renal failure necessitating renal replacement therapy is threatening to reach epidemic proportions over the next decade, and only a small number of countries have robust economies able to meet the challenges posed. A change in global approach to CKD from treatment of end-stage renal disease (ESRD) to much more aggressive primary and secondary prevention is therefore imperative. In this Seminar, we examine the epidemiology of CKD worldwide, with emphasis on early detection and prevention, and the feasibility of methods for detection and primary prevention of CKD. We also review the risk factors and markers of progressive CKD. We explore current understanding of the mechanisms underlying renal scarring leading to ESRD to inform on current and future interventions as well as evidence relating to interventions to slow the progression of CKD. Finally, we make strategic recommendations based on future research to stem the worldwide growth of CKD. Consideration is given to health economics. A global and concerted approach to CKD must be adopted in both more and less developed countries to avoid a major catastrophe.

Measuring quality in arthritis care: The Arthritis Foundation's quality indicator set for analgesics

OBJECTIVE

To develop systematically validated quality indicators (QIs) addressing analgesic safety.

METHODS

A comprehensive literature review of existing quality measures, clinical guidelines, and evidence supporting potential QIs concerning nonselective (traditional) nonsteroidal anti-inflammatory drugs (NSAIDs) and newer cyclooxygenase 2-selective NSAIDs was undertaken. An expert panel then validated or refuted potential indicators utilizing a proven methodology.

RESULTS

Eleven potential QIs were proposed. After panel review, 8 were judged to be valid; an additional 10 were proposed by the panel, of which 7 were rated as valid. Quality indicators focused upon informing patients about risk, NSAID choice and gastrointestinal prophylaxis, and side effect monitoring.

CONCLUSION

The 15 validated indicators were combined, where appropriate, to yield 10 validated processes of care indicators for the safe use of NSAIDs. These indicators developed by literature review and finalized by our expert panel process can serve as a basis to compare the quality of analgesic use provided by health care providers and delivery systems.

Analgesic use and change in kidney function in apparently healthy men

BACKGROUND

Studies using a single creatinine measurement have yielded inconsistent results regarding analgesic use and kidney function.

METHODS

This is a prospective cohort study of 4,494 US male physicians who provided blood samples in both 1982 and 1996. Outcomes measured were increase in plasma creatinine level of 0.3 mg/dL or greater (> or =26.5 micromol/L) and decline in glomerular filtration rate (GFR) of 29.0 mL/min/1.73 m2 or greater during this 14-year period. Self-reported use of aspirin, acetaminophen, and other nonsteroidal anti-inflammatory drugs (NSAIDs) was classified as never (<12 pills during the study period), 12 to 1,499 pills, 1,500 to 2,499 pills, and 2,500 or greater pills during the study period.

RESULTS

Blood measurements made 14 years apart showed increased creatinine levels in 242 participants and decreased GFRs in 224 participants. Compared with never use, multivariable-adjusted odds ratios (ORs) of increased creatinine levels were 0.98 (95% confidence interval [CI], 0.43 to 2.23) for 2,500 or greater pills of aspirin, 1.02 (95% CI, 0.55 to 1.90) for 2,500 or greater pills of acetaminophen, and 1.12 (95% CI, 0.67 to 1.87) for 2,500 or greater pills of other NSAIDs. For decreased GFRs, ORs for intake of 2,500 or greater pills were 0.75 (95% CI, 0.35 to 1.57) for aspirin, 1.22 (95% CI, 0.66 to 2.26) for acetaminophen, and 1.11 (95% CI, 0.65 to 1.90) for other NSAIDs. Use of aspirin, but not acetaminophen or other NSAIDs, was associated with a reduced risk for change in kidney function in participants without cardiovascular risk factors and a possible but nonsignificant increase in those with cardiovascular risk factors.

CONCLUSION

Occasional to moderate analgesic intake of aspirin, acetaminophen, or NSAIDs does not appear to increase the risk for decline in kidney function during a period of 14 years.

Caffeine as a promoter of analgesic-associated nephropathy--where is the evidence?

Individual groups of nephrologists - in their responsibility for their patients - initiated a most controversial discussion whether or not caffeine - coformulated to analgesics - might initiate or sustain analgesic overdosing. The original sources (data) of such suspicion have got lost during the debate of the last two decades. Therefore, it seemed to be appropriate to investigate the original data background and the reasons why nephrologists started to suspect caffeine as a stimulant of analgesic overdosing by employing a systematic and exhaustive review of primary nephrological publications. Their selection followed a precise selection plan, including all epidemiological studies on analgesic-associated nephropathy, the original papers of all groups having been involved in those studies, further originals from the mainly involved countries (academically, politically), and any literature thereof cited as a proof. The following results emerged from the investigation: (i) The epidemiological studies warranted no conclusion about a role of caffeine in prompting excessive analgesic use. (ii) The identified groups of nephrologists provided not substantial data to advocate the said suspicion, except for the observation of a preferential choice of phenacetin-containing combinations, especially powder preparations. (iii) Only two cited original data sources revealed drug-seeking behaviour with phenacetin-containing preparations which subsided, after phenacetin was banned from the respective markets. Conclusively, it appears that there is no substantial data to support a pivotal role of caffeine in initiating or sustaining analgesic overdosing. However, there is strong data that phenacetin, by its psychotropic properties, may have caused drug-seeking behaviour and thus led to analgesic overdosing. This conclusion is convincingly supported by thorough pharmacokinetic investigations. Note: All caffeine-related statements within the reviewed literature have been collected in tables (referred to as Table SX) which are provided in full text for check on the following website: http://www.blackwellpublishing.com/products/journals/suppmat/FCP/FCP174/FCP174sm.htm

A benefit-risk assessment of caffeine as an analgesic adjuvant

Caffeine has been an additive in analgesics for many years. However, the analgesic adjuvant effects of caffeine have not been seriously investigated since a pooled analysis conducted in 1984 showed that caffeine reduces the amount of paracetamol (acetaminophen) necessary for the same effect by approximately 40%. In vitro and in vivo pharmacological research has provided some evidence that caffeine can have anti-nociceptive actions through blockade of adenosine receptors, inhibition of cyclo-oxygenase-2 enzyme synthesis, or by changes in emotion state. Nevertheless, these actions are only considered in some cases. It is suggested that the actual doses of analgesics and caffeine used can influence the analgesic adjuvant effects of caffeine, and doses that are either too low or too high lead to no analgesic enhancement. Clinical trials suggest that caffeine in doses of more than 65 mg may be useful for enhancement of analgesia. However, except for in headache pain, the benefits are equivocal. While adding caffeine to analgesics increases the number of patients who become free from headache [rate ratio = 1.36, 95% confidence interval (CI) 1.17 to 1.58], it also leads to more patients with nervousness and dizziness (relative risk = 1.60, 95% CI 1.26 to 2.03). It is suggested that long-term use or overuse of analgesic medications is associated with rebound headache. However, there is no robust evidence that headache after use or withdrawal of caffeine-containing analgesics is more frequent than after other analgesics. Case-control studies have shown that caffeine-containing analgesics are associated with analgesic nephropathy (odds ratio = 4.9, 95% CI 2.3 to 10.3). However, no specific contribution of caffeine to analgesic nephropathy can be identified from these studies. Whether caffeine produces nephrotoxicity on its own, or increases nephrotoxicity due to analgesics, is yet to be established.

[Prevalence of chronic renal failure in primary care]

OBJECTIVE

To determine the prevalence of chronic renal failure (CRF) without replacement treatment (RT), and to describe the primary renal diseases and associated risk factors that might favour its evolution to terminal renal failure. Design. Cross-sectional, descriptive study.

SETTING

Population attended at a primary care centre (PCC).

PARTICIPANTS

Over-14s with a clinical history opened at the Bon Pastor PCC.

RESULTS

Between the 1st of January 1997 and the 1st of December 1997, 12241 clinical histories were reviewed. 64 patients were identified who satisfied criteria of CRF without RT, a prevalence of 5228 patients per million inhabitants (95% CI, 3,950-6,510). 71.9% were men, and mean age was 72 (SD, 13.5). The most recent plasma creatinine averaged 2 mg/dl (SD, 0.66). Frequency according to kind of nephropathy was: 3 (4.7%) glomerular, 5 (7.8%) diabetic, 3 (4.7%) interstitial, 41 (64.1%) vascular (hypertension), 2 (3.1%) indeterminate and 10 (15.6%) unclassifiable. Associated risk factors in these patients were: 47 (73.4%) with hypertension, 16 (25%) diabetic, 26 (40.6%) with hypercholesterolaemia, 20 (31.3%) chronic consumers of analgesics, and 10 (15.6%) smokers. 51.6% of the patients suffered other cardiovascular illnesses.

CONCLUSIONS

The estimated prevalence in the population of CRF without RT is 5,228 per million inhabitants. Hypertension is the risk factor most closely associated with this pathology.

Acetaminophen, aspirin, and chronic renal failure

BACKGROUND

Several epidemiologic studies have demonstrated an association between heavy consumption of nonnarcotic analgesics and the occurrence of chronic renal failure, but it is unclear which is the cause and which is the effect

METHODS

In a nationwide, population-based, case-control study of early-stage chronic renal failure in Sweden, face-to-face interviews were conducted with 926 patients with newly diagnosed renal failure and 998 control subjects, of whom 918 and 980, respectively, had complete data. We used logistic-regression models to estimate the relative risks of disease-specific types of chronic renal failure associated with the use of various analgesics

RESULTS

Aspirin and acetaminophen were used regularly by 37 percent and 25 percent, respectively, of the patients with renal failure and by 19 percent and 12 percent, respectively, of the controls. Regular use of either drug in the absence of the other was associated with an increase by a factor of 2.5 in the risk of chronic renal failure from any cause. The relative risks rose with increasing cumulative lifetime doses, rose more consistently with acetaminophen use than with aspirin use, and were increased for most disease-specific types of chronic renal failure. When we disregarded the recent use of analgesics, which could have occurred in response to antecedents of renal disease, the associations were only slightly attenuated

CONCLUSIONS

Our results are consistent with the existence of exacerbating effects of acetaminophen and aspirin on chronic renal failure. However, we cannot rule out the possibility of bias due to the triggering of analgesic consumption by predisposing conditions.

Epidemiologic assessment of the safety of conventional nonsteroidal anti-inflammatory drugs

The use of conventional nonsteroidal anti-inflammatory drugs (NSAIDs) has been associated with upper gastrointestinal bleeding and perforation (UGIB), acute liver injury, acute renal injury, heart failure, and adverse reproductive outcomes. This article summarizes the effects of various factors, such as NSAID dose, duration of treatment, patient age, and ulcer history, on the incidences of these adverse side effects. We used the UK General Practice Research Database to study further the principal safety concern related to NSAIDs, namely, UGIB.

Relationship between nonphenacetin combined analgesics and nephropathy: a review. Ad Hoc Committee of the International Study Group on Analgesics and Nephropathy

BACKGROUND

The debate on the association between nonphenacetin-containing combined analgesics and renal disease has lasted for several years.

METHOD

A peer review committee of scientists, selected jointly by the regulatory authorities of Germany, Switzerland, and Austria and the pharmaceutical industry was asked to critically review data on the relationship between nonphenacetin combined analgesics and nephropathy.

RESULTS

The committee regarded epidemiologic evidence on nonphenacetin combined analgesics as inconclusive because of sparse information and substantial methodological problems. The committee also noted that a diagnosis of analgesic-associated nephropathy (AAN) in clinical practice usually depends on information about exposure before or in the early stages of the disease and is seldom accompanied by specific histologic evidence. The morphologic finding of papillary calcification can arise from other conditions and is not specific for AAN. For these reasons, the identification criteria for AAN should be reappraised with scientific methods to validate the diagnostic procedure. In the limited amount of experimental pharmacological data in humans and animals, the committee found no convincing evidence to confirm or refute the hypothesis that nonphenacetin combined analgesics are more nephrotoxic than single formulations. For caffeine taken with combined analgesics, the currently available information is not sufficient to postulate a harmful toxicological effect.

CONCLUSION

The committee's two main conclusions were that sufficient evidence is absent to associate nonphenacetin combined analgesics with nephropathy and that new studies should be done to provide appropriate data for resolving the question.

The renal effects of nonsteroidal anti-inflammatory drugs in older people: findings from the Established Populations for Epidemiologic Studies of the Elderly

OBJECTIVE

To determine whether older people who use nonsteroidal anti-inflammatory agents (NSAIDs) have increased levels of blood urea nitrogen (BUN), serum creatinine, and BUN:serum creatinine ratio.

DESIGN

Cross-sectional, secondary data analysis.

SETTING

Older people living in the communities of East Boston, MA, New Haven, CT, and Washington and Iowa Counties, Iowa.

PARTICIPANTS

A total of 4099 people aged 70 years or older who were participants in the National Institute on Aging's Established Populations for Epidemiologic Studies of the Elderly project, had survived to the 6-year follow-up interview and had consented to the blood drawing.

MEASUREMENTS

We assessed use of the NSAIDs at the 3- and 6-year interviews through a drug inventory and visual review of medication containers. Markers of renal function assessed through analysis of blood samples drawn at the time of the interview included BUN and creatinine.

RESULTS

Fifteen percent of the cohort reported use of NSAIDs during the 2 weeks preceding the 6-year interview. Controlling for age, sex, and a range of potential confounding variables, NSAID users had significant prevalence odds ratios of 1.9 (95% confidence interval (CI), 1.5-2.3) for being in the highest quartile of BUN (>23), 1.3 (CI 1.1-1.7) for the highest quartile of serum creatinine (> or =1.4), and 1.7 (CI 1.4-2.1) for the highest quartile of the BUN:creatinine ratio (> or = 19.4). Chronic NSAID users (those who reported NSAID use at both the 3-year and 6-year interviews) accounted for the increased risk of high serum creatinine levels.

CONCLUSION

Community-dwelling older people who use NSAIDs tend to have higher levels of common laboratory markers of renal dysfunction. This hypothesis requires further testing in prospective cohort studies designed a priori to evaluate these issues.

Analgesic nephropathy: is it caused by multi-analgesic abuse or single substance use?

Analgesic nephropathy is a slowly progressive renal disease, characterised by renal papillary necrosis. Recently, diagnostic criteria for this disease have been defined based on renal computed tomography scanning performed without contrast. The observation of a decreased renal mass of both kidneys, combined with either bumpy contours or papillary calcifications, has been found to have high diagnostic specificity and sensitivity. However, the question remains as to what kind of analgesics can cause analgesic nephropathy. In the majority of early reports about this condition, phenacetin was singled out as the nephrotoxic culprit. However, during the last decade the nephrotoxic potential of nonphenacetin-containing preparations has become apparent. It is clear that people who abuse analgesics prefer combination analgesics containing 2 analgesics combined with caffeine and/or codeine. In contrast, abuse of products containing only aspirin (acetylsalicylic acid) or paracetamol (acetaminophen) is seldom described and associated renal disease is only occasionally reported. Experimental evidence of the nephrotoxicity of analgesic preparations is not well established. The results of studies involving analgesic administration in animals remain contradictory. Clinical evidence linking high consumption of analgesic preparations with analgesic nephropathy is overwhelming. Most patients who admit to over-consuming analgesics have taken preparation containing more than one compound. In recent years, it has become more apparent that preparations not containing phenacetin also have the potential to cause nephrotoxicity manifesting as identical renal lesions. Further epidemiological evidence of the nephrotoxic potential of analgesic combinations has come from case-control studies published during the last decade and from 2 prospective cohort studies. Effective prevention of analgesic nephropathy consists of the prohibition of over-the-counter sales of preparation containing at least 2 analgesics associated with caffeine and/or codeine.

A safety assessment of fixed combinations of acetaminophen and acetylsalicylic acid, coformulated with caffeine

Overuse and abuse of phenacetin-containing mixed analgesics has contributed to end-stage renal disease. Combination analgesics, especially those coformulated with caffeine, have been implicated as imparting a greater risk of analgesic-associated nephropathy (AAN) than single or coformulated analgesics without caffeine. This has led to a recommendation that the sale of "two plus caffeine" analgesic mixtures be reclassified from over-the-counter to prescription only availability. There is a rational basis for coformulating acetylsalicylic acid (ASA) and acetaminophen (paracetamol) as this reduces the dose of each, without altering efficacy. The coformulation of caffeine with these analgesics has a significant adjuvant effect and increases analgesic efficacy 1.4-1.6-fold. Currently available animal and human data do not support the notion that the nephrotoxic risk from coformulated ASA and acetaminophen is higher than the risk from either ASA or acetaminophen alone, in equivalent analgesic doses. There are no epidemiological data that implicate caffeine in AAN, and only limited evidence that links excessive acetaminophen usage to renal disease. There is no evidence that caffeine increases analgesics papillotoxicity directly. The presence of caffeine in mixtures of analgesics are no more addictive than other sources of caffeine. There is no evidence to suggest that adding caffeine to analgesic mixtures enhances the potential for promoting analgesic misuse in the general population. Thus distinct therapeutic benefits of ASA, acetaminophen and caffeine appear to outweigh any known risk. It is doubtful if preventing the availability of these products will significantly affect the role of analgesic abuse/overuse in end-stage renal disease. Better risk management would come from a focused educational program, developed in a close collaboration between industry, healthcare professionals and consumer organizations, such a program must warn against the potential dangers of analgesic and non-steroidal anti-inflammatory drug misuse.

Analgesic use and chronic renal failure: a critical review of the epidemiologic literature

Heavy use of analgesics, particularly over-the-counter (OTC) products, has long been associated with chronic renal failure. Most of the earlier reports implicated phenacetin-containing analgesics as the risk factor. Since the early 1980s. several case-control studies have reported associations between chronic renal failure and use of other forms of analgesics, including acetaminophen, aspirin, and other non-steroidal antiinflammatory drugs (NSAIDs). Findings from these studies, however. should be interpreted with caution because of a number of inherent limitations and potential biases in the study design and data collection procedures. These limitations include: failure to identify patients early enough in the natural history of their disease to collect reliable information on analgesic use at an etiologically relevant time period; selection bias due to incomplete identification of subjects or low response rates; selection of cases and controls from different population bases; failure to employ survey techniques to improve reliability of recall of analgesic use; failure to collect detailed information on analgesic use such as year started and ended and reasons for switching analgesics; lack of standardization in the definition of regular analgesic use; and failure to adjust for phenacetin use and other confounding factors when assessing associations with analgesics other than those containing phenacetin. It is our hope that this review of study design limitations will lead to improvements in future studies of chronic renal failure risk. Since use of analgesics is widespread and new OTC products are introduced frequently, the potential impact of these drugs on the development of chronic renal failure may be significant, thus warranting continued evaluation of these products for any renal toxicity.

Analgesic abuse in the elderly. Renal sequelae and management

Nephropathy caused by the use of 'classical' analgesics [paracetamol (acetaminophen), salicylates and pyrazolone derivatives] and renal impairment associated with nonsteroidal anti-inflammatory drugs (NSAIDs) are important health problems in the elderly. Classical analgesic nephropathy is a chronic renal disease characterised by renal papillary necrosis and chronic interstitial nephritis. The nephropathy is caused by the excessive consumption of analgesic mixtures containing at least 2 antipyretic analgesics combined with caffeine and/or codeine. The use of NSAIDs is associated with a wide range of tubular, interstitial, glomerular and vascular renal lesions. Despite the well-characterised acute biological effects of NSAIDs on the kidney, there is only limited evidence that they are associated with an increased risk of chronic renal failure. Classical analgesic toxicity can be effectively prevented by limiting the availability of over-the-counter analgesic mixtures containing 2 analgesic compounds in combination with potentially addictive substances (e.g. caffeine and/or codeine). In the elderly in particular, the prolonged, regular use of NSAIDs should be discouraged. Patients starting NSAID therapy should be monitored regularly and drug interactions should be avoided.

A review of epidemiologic studies of nonnarcotic analgesics and chronic renal disease

The relationship of long-term and heavy exposure of nonnarcotic analgesics to the risk of chronic renal disease (CRD) has been the object of intensive clinical, pharmacologic, toxicologic, and epidemiologic research for 4 decades. The clinical evidence of an increased risk has been suggestive but inconclusive. The experimental evidence in animal models has been inconsistent, and in any case it cannot be generalized to humans. The epidemiologic evidence has been unsatisfactory for the most part: most of the early studies had severe methodologic limitations; moreover, they related mainly to phenacetin-containing drugs and did not have useful information on other analgesics. Since 1980, 9 analytical epidemiologic studies have attempted to confirm that a causal relationship exists between phenacetin or other analgesics and CRD. In the aggregate, despite methodologic flaws, this work suggests that excessive use of phenacetin-containing analgesics probably causes renal papillary necrosis and interstitial nephritis. In contrast, there is no convincing epidemiologic evidence that nonphenacetin-containing analgesics (including acetaminophen, aspirin, and mixtures of these two compounds) or that nonsteroidal antiinflammatory drugs cause CRD. Moreover, the nature of dose-response relationships, the types of renal disease possibly caused by analgesics, and the cofactors that might be related both to analgesic use and to the development of CRD in humans are still uncertain, and the pathologic mechanisms of analgesic-induced CRD in humans remain unclear. It may take many years before all the outstanding issues are settled. Until they are, as a matter of good clinical judgment it would be prudent to consider all analgesics as potentially nephrotoxic and, as much as possible, to avoid excessive, protracted use.

Analgesic nephropathy

At least two distinct forms of analgesic nephropathy are presently recognized. One form is classical analgesic nephropathy that is associated with habitual consumption of predominantly combination analgesic products. This disease takes many years to develop and is characterized by a dense interstitial fibrosis and the insidious development of renal failure. Renal papillary necrosis had been classically associated with this illness. New diagnostic tests to make an early diagnosis of the lesion may be on the horizon with the recognition that the non-contrasted CT scan may be useful. Further studies will be necessary to confirm this in the U.S. population of analgesic users. The second form of analgesic nephropathy is typically an acute renal failure associated with the use of nonsteroidal anti-inflammatory drugs. In part this disease has been predictable based on the fact that there is an at-risk population of patients who are more vulnerable to developing it. Other features of nonsteroidal induced toxicity are also recognized (see Table 3). It is hoped that the increased recognition that chronic and acute analgesic use may lead to renal failure will result in strategies that will apprise consumers and physicians of this risk, and thereby lead to reduction in the prevalence of these two forms of analgesic-related kidney disease.

Clinical consequences of nonnarcotic analgesic use

The accuracy of the economic analysis of the selected adverse events evaluated by McGoldrick and Bailie is questionable. The quantitative perspective on the economics of the adverse events associated with nonnarcotic analgesic use proposed by these authors is limited by the fact that they have combined data on over 30 different NSAIDs into a single value for comparison with two single-entity agents: acetaminophen and aspirin. The relative prevalence of major organ system toxicities varies markedly among the NSAIDs, and this variance invalidates the use of a class conclusion approach. Their conservative incidence estimates, the lack of data in some areas (i.e., hepatic injury), and the exclusion of combination analgesics further limit the utility of their conclusions. However, it is difficult to argue authoritatively that the relative costs of toxicities associated with the three analgesic classes they reviewed are not representative. The ultimate question is, "What is the optimal analgesic for a given patient?" This question can be addressed only if one considers the underlying cause of pain, its chronicity/acuity, the patient's concurrent disease states, if any, and the potential for drug interactions with the patient's concomitant medications. McGoldrick and Bailie concluded on an economic basis that acetaminophen is the analgesic of choice for most patients, including those with impaired renal function. This recommendation is in agreement with those of the Analgesics and the Kidney Ad Hoc Committee of the National Kidney Foundation. It also would seem prudent to use acetaminophen as the first-line agent for those patients in whom aspirin and NSAID use should be avoided or used only with caution along with frequent monitoring of renal function, blood pressure, electrolytes, and/or coagulation status. Thus, there is little to no controversy in their recommendation to initiate treatment with acetaminophen. The authors, however, also suggested that switching patients from an NSAID to acetaminophen would result in significantly decreased costs and morbidity. These authors, however, did not address one key issue that impacts their economic analysis: the relative efficacy of acetaminophen and NSAIDs. If efficacy is similar, then the risk/benefit ratio and economic consequences would favor the use of acetaminophen. However, if many patients are receiving NSAIDs because they did not obtain pain relief with the use of acetaminophen, there would be neither rationale or likely benefit with a change in therapy to acetaminophen. Finally, McGoldrick and Bailie did not evaluate an issue that has perhaps the most far-reaching consequence. Many OTC analgesics are currently marketed as combinations of aspirin, acetaminophen, salicylamide, or caffeine (Table 2). Although the intent of these combinations was [Table: see text] to enhance efficacy while minimizing adverse events, it is now apparent that at least concerning adverse events, the goal was not achieved. Therefore, in light of the markedly higher risk for renal injury with combination analgesics, these agents should be withdrawn from the marketplace. While some might argue that patient education is the key and that addition of an explicit warning on the label of OTC combination products should be an adequate intervention, this agreement is not supported by the Belgium experience. The removal of combination analgesics from the OTC marketplace could be accomplished by governmental action, such as the ban on phenacetin over 10 years ago. Alternatively, pharmacists could no longer sell these products and counsel patients on the rational use of OTC analgesics. The choice among single-entity agents could then be individualized on the basis of patient's current medical status and the adverse event profile of the available agents.