In this task, you are given a passage which has a question and the context. You have to generate an answer to the question based on the information present in the context.

[EX Q]: Context: Anti-epileptic drugs (AEDs) and the ketogenic diet (KD) are often used concomitantly in children with refractory epilepsy. It has been hypothesised that certain AEDs may interfere with KD. The purpose of this study was to elucidate relationships between efficacy of KD and use of specific AEDs.', "A retrospective study was performed in 71 children with refractory epilepsy starting the KD between 2008 and 2014 in Erasmus University Hospital Sophia Children's Hospital. Efficacy of the KD (defined as 50% seizure reduction) was evaluated after three months of treatment and related to the AEDs used.", 'The KD was successful after three months in 61% of the children (N=71). Efficacy was significantly reduced if children (n=16) used lamotrigine (31%) at diet initiation or in the course of the diet, compared to other antiepileptic drugs (69%) (p=0.006). In comparison to children using other antiepileptic drugs, the percentage of children that had adequate ketosis was significantly reduced in case of lamotrigine use (p=0.049).\Question: Is concomitant lamotrigine use associated with decreased efficacy of the ketogenic diet in childhood refractory epilepsy?
[EX A]: Lamotrigine treatment during KD is associated with a decreased efficacy of the KD.

[EX Q]: Context: Monitoring renal function is crucial in children undergoing chemotherapy. To date, a combination of routine serum creatinine (SCR) monitoring with occasional determination of creatinine clearance ratio (CCR) is widely used as clinical standard for this purpose. Both methods have their limitations regarding diagnostic value (SCR) or practicability (CCR), especially in young children. Diagnostic alternatives, such as glomerular filtration rate (GFR) estimation formulas have not been proved to be superior. The aim of the study was to evaluate whether serum cystatin C (CysC) may have a diagnostic impact on pediatric patients.', 'CysC, SCR, several GFR estimation formulas (Counahan-Barratt, Ghazali-Barratt, Schwartz, Shull, Traub), and CCR were studied in 80 pediatric cancer patients (age range: 0.17-17.9 years) during their chemotherapy. Special attention was given to children under the age of 3 in whom accurate urine collection for CCR is difficult.', 'All parameters correlated similarly well with CCR. Total accuracy was 66% and 67% for CysC and SCR, respectively. In very young children (<3 years), correlation with CCR was for CysC r = -0.74 with an area under the curve (AUC) of 0.646, and for SCR r = -0.27 with AUC = 0.594. Total accuracy was 60% for CysC, 50% for SCR.\Question: Is serum cystatin C a suitable marker for routine monitoring of renal function in pediatric cancer patients , especially of very young age?
[EX A]: CysC represents a suitable marker for monitoring renal function in pediatric cancer patients. In young children (<3 years), CysC may have a better diagnostic value than SCR. Future studies should show if CysC can improve renal monitoring by replacing SCR, especially in very young children.

[EX Q]: Context: Although chest radiography is quick and inexpensive, previous research suggests that it is often misleading in emergency department (ED) patients with decompensated heart failure, resulting in misdiagnosis and inappropriate treatment. This study determines the rate of negative chest radiography results in patients found to have disease and the potential contribution of negative findings to a diagnosis discordant with heart failure by an emergency physician.', 'We used data from the Acute Decompensated Heart Failure National Registry (ADHERE), a registry of patients with a primary hospital discharge diagnosis of heart failure. We compared initial ED admitting diagnosis to the criterion standard of a hospital discharge diagnosis of heart failure and related these to radiographic findings of heart failure (interstitial edema, pulmonary edema, or vascular congestion, as determined by a staff radiologist) for patients first treated in the ED. The proportion of patients with a non-heart failure ED diagnosis and the diagnostic sensitivity of radiographic findings of heart failure are calculated.', 'There were 85,376 patients with chest radiograph results and an ED admitting diagnosis. Overall, there were 15,937 patients with no signs of congestion on ED chest radiography, giving a negative rate of 18.7% (95% confidence interval [CI] 18.4% to 18.9%). The proportion of patients with an ED non-heart failure admitting diagnosis was higher in patients with a negative chest radiograph result (23.3%; 95% CI 22.6% to 23.9%) than in patients with a positive chest radiograph result (13.0%; 95% CI 12.7% to 13.2%).\Question: Does prevalence of negative chest radiography result in the emergency department patient with decompensated heart failure?
[EX A]:
Approximately 1 of every 5 patients admitted from the ED with acute decompensated heart failure had no signs of congestion on chest radiography. Patients lacking signs of congestion on ED chest radiography were more likely to have an ED non-heart failure diagnosis than patients with signs of congestion. Clinicians should not rule out heart failure in patients with no radiographic signs of congestion.