Comprehensive evaluation of two HLA-B17 monoclonal antibodies for flow cytometry-based HLA-B57/B58 screening prior to abacavir prescription

Hypersensitivity reactions to the drug abacavir, used to treat HIV/AIDS patients, is associated with possession of HLA-B*57:01. We have carefully assessed two commercially available HLA-B57/B58 murine monoclonal antibodies [0196HA and BIH0243 (One Lambda Inc.)] in a simple flow cytometry-based assay. The evaluation involved tests on 228 reference and random samples covering 91% of all WHO recognized HLA-A, B and C specificities. These involved donors with six different HLA-B*57 alleles and included 19 examples of B*57:01. Both antibodies unambiguously detected B57, but there were small difference in their reactivity against B57-positive non-B*57:01 samples. Importantly, there was no reactivity against B57/B58-negative samples. The possible amino acid motifs involved in the reactivity of these antibodies with B57/B58 were delineated. Thus, HLA-B57/B58, normally present in <10% of patients, can be easily recognized using these two antibodies and further tested by a DNA-based typing method to identify B*57:01.

Referral proformas improve compliance to national colorectal 2-week wait targets: does this affect cancer detection rates?

AIM

To facilitate implementation of National Institute for Health and Clinical Excellence (NICE) guidelines for urgent colorectal cancer referral, local cancer networks have promoted the use of standardized proformas in primary care. This clinical audit assessed use of the proforma within the Thames Valley Cancer Network (TVCN) to see whether increased proforma use was associated with higher compliance to NICE guidelines and higher cancer detection rates.

METHOD

All 2-week wait referrals for lower bowel cancer to the six Acute NHS Trusts in the TVCN received during the month of June 2010 were identified, anonymized and analysed in relation to colorectal cancer detection rates.

RESULTS

Of the 586 referrals audited, proforma usage varied significantly across the six Acute NHS Trusts from 18% to 96%. Referral letters from primary care had NICE compliance ranging from 30 to 50%. In those which received a referral protocol, 50-90% were NICE compliant. Proforma use was associated with higher cancer detection rates (P = 0.03).

CONCLUSION

These results have wide-ranging implications since they suggest that the adoption of a simple proforma in primary care can improve the effectiveness of referral for suspected cancer.

Systematic review and validation of prediction rules for identifying children with serious infections in emergency departments and urgent-access primary care

BACKGROUND

Although the vast majority of children with acute infections are managed at home, this is one of the most common problems encountered in children attending emergency departments (EDs) and primary care. Distinguishing children with serious infection from those with minor or self-limiting infection is difficult. This can result in misdiagnosis of children with serious infections, which results in a poorer health outcome, or a tendency to refer or admit children as a precaution; thus, inappropriately utilising secondary-care resources.

OBJECTIVES

We systematically identified clinical features and laboratory tests which identify serious infection in children attending the ED and primary care. We also identified clinical prediction rules and validated those using existing data sets.

DATA SOURCES

We searched MEDLINE, Medion, EMBASE, Cumulative Index to Nursing and Allied Health Literature and Database of Abstracts of Reviews of Effects in October 2008, with an update in June 2009, using search terms that included terms related to five components: serious infections, children, clinical history and examination, laboratory tests and ambulatory care settings. We also searched references of included studies, clinical content experts, and relevant National Institute for Health and Clinical Excellence guidelines to identify relevant studies. There were no language restrictions. Studies were eligible for inclusion if they were based in ambulatory settings in economically developed countries.

REVIEW METHODS

Literature searching, selection and data extraction were carried out by two reviewers. We assessed quality using the quality assessment of diagnostic accuracy studies (QUADAS) instrument, and used spectrum bias and validity of the reference standard as exclusion criteria. We calculated the positive likelihood ratio (LR+) and negative likelihood ratio (LR-) of each feature along with the pre- and post-test probabilities of the outcome. Meta-analysis was performed using the bivariate method when appropriate. We externally validated clinical prediction rules identified from the systematic review using existing data from children attending ED or primary care.

RESULTS

We identified 1939 articles, of which 35 were selected for inclusion in the review. There was only a single study from primary care; all others were performed in the ED. The quality of the included studies was modest. We also identified seven data sets (11,045 children) to use for external validation. The most useful clinical features for ruling in serious infection was parental or clinician overall concern that the illness was different from previous illnesses or that something was wrong. In low- or intermediate-prevalence settings, the presence of fever had some diagnostic value. Additional red flag features included cyanosis, poor peripheral circulation, rapid breathing, crackles on auscultation, diminished breath sounds, meningeal irritation, petechial rash, decreased consciousness and seizures. Procalcitonin (LR+ 1.75-2.96, LR- 0.08-0.35) and C-reactive protein (LR+ 2.53-3.79, LR- 0.25-0.61) were superior to white cell counts. The best performing clinical prediction rule was a five-stage decision tree rule, consisting of the physician's gut feeling, dyspnoea, temperature ≥ 40 °C, diarrhoea and age. It was able to decrease the likelihood of serious infections substantially, but on validation it provided good ruling out value only in low-to-intermediate-prevalence settings (LR- 0.11-0.28). We also identified and validated the Yale Observation Scale and prediction rules for pneumonia, meningitis and gastroenteritis.

LIMITATIONS

Only a single study was identified from primary-care settings, therefore results may lack generalisability.

CONCLUSIONS

Several clinical features are useful to increase or decrease the probability that a child has a serious infection. None is sufficient on its own to substantially raise or lower the risk of serious infection. Some are highly specific ('red flags'), so when present should prompt a more thorough or repeated assessment. C-reactive protein and procalcitonin demonstrate similar diagnostic characteristics and are both superior to white cell counts. However, even in children with a serious infection, red flags will occur infrequently, and their absence does not lower the risk. The diagnostic gap is currently filled by using clinical 'gut feeling' and diagnostic safety-netting, which are still not well defined. Although two prediction rules for serious infection and one for meningitis provided some diagnostic value, we do not recommend widespread implementation at this time. Future research is needed to identify predictors of serious infection in children in primary-care settings, to validate prediction rules more widely, and determine the added value of blood tests in primary-care settings.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Differences in insulin treatment satisfaction following randomized addition of biphasic, prandial or basal insulin to oral therapy in type 2 diabetes

AIM

No differences in patient health status as measured by the EuroQol-5 Dimension (EQ-5D) questionnaire were observed at 1 year between groups randomized to addition of biphasic, prandial or basal insulin to oral therapy in the treat-to-target in type 2 diabetes trial. We further investigated insulin treatment satisfaction between groups.

METHODS

Seven hundred and eight patients with suboptimal glycated haemoglobin levels (7.0-10.0%) taking maximally tolerated doses of metformin and sulphonylurea were randomized to biphasic insulin aspart twice-daily, prandial insulin aspart three times daily or basal insulin detemir once-daily (twice if required). At 1 year self-completed Insulin Treatment Satisfaction Questionnaires (ITSQ) were administered. Lower scores indicated lower treatment satisfaction. We tested for differences between the three groups for the ITSQ total score and for each of the five ITSQ domain scores adjusting for age, gender, ethnicity and education.

RESULTS

All 22 ITSQ subscales were completed by 554 (78.2%) patients. Their mean (s.d.) age was 61.5 (9.4) years, body weight 86.1 (16) kg and median (IQR) diabetes duration 9 (6-13) years. Sixty-five percent (358) were male. Median (IQR) 1-year ITSQ total score was lower in patients allocated to prandial therapy (76.5, 68.0-88.6) than in patients allocated to biphasic insulin (83.3, 74.2-90.2) or basal insulin (84.1, 73.5-93.2). With the exception of 'perceived glycaemic control', 1-year adjusted ITSQ scores were significantly different between groups for each of the ITSQ domains, with lower scores for prandial insulin compared with the basal or biphasic groups. Median (IQR) ITSQ scores were lower in patients with a gain in body mass index (BMI) > 1.23 kg/m² over 1 year (79.5, 69.7-89.4) compared to those with a lesser or no gain in BMI (84.1, 74.2-92.4) and in those with occurrence of hypoglycaemia (79.5, 69.7-88.6) compared to those with no hypoglycaemia (84.1, 73.7-93.2).

CONCLUSION

Specific measurement of insulin treatment satisfaction identifies differences between regimens used to intensify treatment for type 2 diabetes. Impact of treatment on lifestyle needs to be considered as a factor in the choice of an insulin regimen.