Impact of compliance to oral cysteamine treatment on the costs of Kidney failure in patients with nephropathic cystinosis in the United Kingdom

BACKGROUND

Nephropathic Cystinosis (NC), a rare disease characterised by intra-lysosomal accumulation of cystine, results in progressive kidney failure (KF). Compliance to lifelong oral cysteamine, the only therapy, is often compromised. The relationship between compliance and costs of NC has not been previously formally assessed. The present study evaluates the impact of compliance on lifetime (direct) costs of treating KF in NC patients in the United Kingdom.

METHODS

A three-state (KF-free, post-KF, death) partitioned survival model was developed for hypothetical 'Good Compliance' (GC) and 'Poor Compliance' (PC) cohorts. Survival in the KF-free state was determined by a published regression function of composite compliance score (CCS). The CCS is a summation of annual compliance scores (ACS) over treatment duration prior to KF. ACSs are indexed on annual (average) leukocyte cystine levels (LCL). The Poor Compliance cohort was defined to reflect NC patients in a previous study with a mean LCL of 2.35 nmols nmol half-cystine/mg protein over the study period - and an estimated mean ACS of 1.64 over a 13.4 year treatment duration. The Good Compliance cohort was assumed to have an ACS of 2.25 for 21 years. Major KF costs were evaluated - i.e., dialysis, kidney transplants, and subsequent monitoring.

RESULTS

The mean CCS was 47 for the GC and 22 for the PC cohort respectively, corresponding to estimated lifetime KF costs of £92,370 and £117,830 respectively - i.e., a cost saving of £25,460/patient, or £1,005/patient for every 1-unit improvement in CCS.

CONCLUSION

This analysis indicates that lifetime costs of KF in NC can be reduced through improved treatment compliance with oral cysteamine.

Metabolic mayhem. The advantage of keeping your nose both in the books and in the nappy!

This case presentation takes you on a journey of diagnostic hurdles, covering a common neonatal presentation: abdominal distention with failure to pass meconium, followed by a presentation in infancy with metabolic, renal and electrolyte abnormalities. The article provides a systematic approach to the different clinical problems, allowing interpretation of results, making differential diagnoses and deciding on investigations and management.

The Diagnosis of Urinary Tract infection in Young children (DUTY): a diagnostic prospective observational study to derive and validate a clinical algorithm for the diagnosis of urinary tract infection in children presenting to primary care with an acute illness

BACKGROUND

It is not clear which young children presenting acutely unwell to primary care should be investigated for urinary tract infection (UTI) and whether or not dipstick testing should be used to inform antibiotic treatment.

OBJECTIVES

To develop algorithms to accurately identify pre-school children in whom urine should be obtained; assess whether or not dipstick urinalysis provides additional diagnostic information; and model algorithm cost-effectiveness.

DESIGN

Multicentre, prospective diagnostic cohort study.

SETTING AND PARTICIPANTS

Children < 5 years old presenting to primary care with an acute illness and/or new urinary symptoms.

METHODS

One hundred and seven clinical characteristics (index tests) were recorded from the child's past medical history, symptoms, physical examination signs and urine dipstick test. Prior to dipstick results clinician opinion of UTI likelihood ('clinical diagnosis') and urine sampling and treatment intentions ('clinical judgement') were recorded. All index tests were measured blind to the reference standard, defined as a pure or predominant uropathogen cultured at ≥ 10(5) colony-forming units (CFU)/ml in a single research laboratory. Urine was collected by clean catch (preferred) or nappy pad. Index tests were sequentially evaluated in two groups, stratified by urine collection method: parent-reported symptoms with clinician-reported signs, and urine dipstick results. Diagnostic accuracy was quantified using area under receiver operating characteristic curve (AUROC) with 95% confidence interval (CI) and bootstrap-validated AUROC, and compared with the 'clinician diagnosis' AUROC. Decision-analytic models were used to identify optimal urine sampling strategy compared with 'clinical judgement'.

RESULTS

A total of 7163 children were recruited, of whom 50% were female and 49% were < 2 years old. Culture results were available for 5017 (70%); 2740 children provided clean-catch samples, 94% of whom were ≥ 2 years old, with 2.2% meeting the UTI definition. Among these, 'clinical diagnosis' correctly identified 46.6% of positive cultures, with 94.7% specificity and an AUROC of 0.77 (95% CI 0.71 to 0.83). Four symptoms, three signs and three dipstick results were independently associated with UTI with an AUROC (95% CI; bootstrap-validated AUROC) of 0.89 (0.85 to 0.95; validated 0.88) for symptoms and signs, increasing to 0.93 (0.90 to 0.97; validated 0.90) with dipstick results. Nappy pad samples were provided from the other 2277 children, of whom 82% were < 2 years old and 1.3% met the UTI definition. 'Clinical diagnosis' correctly identified 13.3% positive cultures, with 98.5% specificity and an AUROC of 0.63 (95% CI 0.53 to 0.72). Four symptoms and two dipstick results were independently associated with UTI, with an AUROC of 0.81 (0.72 to 0.90; validated 0.78) for symptoms, increasing to 0.87 (0.80 to 0.94; validated 0.82) with the dipstick findings. A high specificity threshold for the clean-catch model was more accurate and less costly than, and as effective as, clinical judgement. The additional diagnostic utility of dipstick testing was offset by its costs. The cost-effectiveness of the nappy pad model was not clear-cut.

CONCLUSIONS

Clinicians should prioritise the use of clean-catch sampling as symptoms and signs can cost-effectively improve the identification of UTI in young children where clean catch is possible. Dipstick testing can improve targeting of antibiotic treatment, but at a higher cost than waiting for a laboratory result. Future research is needed to distinguish pathogens from contaminants, assess the impact of the clean-catch algorithm on patient outcomes, and the cost-effectiveness of presumptive versus dipstick versus laboratory-guided antibiotic treatment.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

The management of acute hyperkalaemia in neonates and children

This review article describes the pathophysiology and common aetiologies of hyperkalaemia including pseudohyperkalaemia, renal impairment, medication, rhabdomyolysis and aldosterone deficiency. Two clinical cases are used to describe symptoms (mainly muscle weakness and arrhythmias) and illustrate different management options. An approach to management including relevant investigations and interpretation of ECG changes is described. Emergency drug treatments are outlined and the effectiveness of individual therapeutic methods in reducing the potassium concentration described. Chronic management is mentioned but is outside the scope of this article. Hyperkalaemia is a rare but potentially life threatening emergency. It is a manifestation of a disease and therefore the incidence in children is not known. Quick and effective intervention may be necessary and clinicians must be adept at managing this condition. This overview provides two clinical scenarios and summarises aetiologies, investigations and management.

Oral or topical nasal steroids for hearing loss associated with otitis media with effusion in children

BACKGROUND

Otitis media with effusion (OME) is common and may cause hearing loss with associated developmental delay. Treatment remains controversial.

OBJECTIVES

To examine the evidence for treating children with hearing loss associated with OME with systemic or topical intranasal steroids.

SEARCH STRATEGY

We searched the Cochrane ENT Group Trials Register; CENTRAL; PubMed; EMBASE; CINAHL; Web of Science; BIOSIS Previews; Cambridge Scientific Abstracts; mRCT and additional sources for published and unpublished trials. The date of the most recent search was 26 August 2010.

SELECTION CRITERIA

Randomised controlled trials of oral and topical intranasal steroids, either alone or in combination with another agent such as an oral antibiotic. We excluded publications in abstract form only; uncontrolled, non-randomised or retrospective studies; and studies reporting outcomes by ears (rather than children).

DATA COLLECTION AND ANALYSIS

The authors independently extracted data from the published reports using standardised data extraction forms and methods. We assessed the quality of the included studies using the Cochrane 'Risk of bias' tool. We expressed dichotomous results as a risk ratio (RR) and continuous data as weighted mean difference (WMD), both with 95% confidence intervals (CI). Where feasible we pooled studies using a random-effects model and performed tests for heterogeneity between studies. In trials with a cross-over design, we did not use post cross-over treatment data.

MAIN RESULTS

We included 12 medium to high-quality studies with a total of 945 participants. No study documented hearing loss associated with OME prior to randomisation. The follow-up period was generally limited, with only one study of intranasal steroid reporting outcome data beyond six months. There was no evidence of benefit from steroid treatment (oral or topical) in terms of hearing loss associated with OME. Pooled data using a fixed-effect model for OME resolution at short-term follow up (< 1 month) showed a significant effect of oral steroids compared to control (RR 4.48; 95% CI 1.52 to 13.23; Chi² 2.75, df = 2, P = 0.25; I² = 27%). Oral steroids plus antibiotic also resulted in an improvement in OME resolution compared to placebo plus antibiotic at less than one month follow up, using a random-effects model (RR 1.99; 95% CI 1.14 to 3.49; five trials, 409 children). However, there was significant heterogeneity between studies (P < 0.01, I² = 69%). There was no evidence of beneficial effect on OME resolution at greater than one month follow up with oral steroids (used alone or with antibiotics) or intranasal steroids (used alone or with antibiotics) at any follow-up period. There was also no evidence of benefit from steroid treatment (oral or topical) in terms of symptoms.

AUTHORS' CONCLUSIONS

While oral steroids, especially when used in combination with an oral antibiotic, lead to a quicker resolution of OME in the short term, there is no evidence of longer-term benefit and no evidence that they relieve symptoms of hearing loss. We found no evidence of benefit from treatment of OME with topical intranasal steroids, alone or in combination with an antibiotic, either at short or longer-term follow up.