Validation of immune thrombocytopenia diagnosis code in the French hospital electronic database

Development and Validation of a Model to Identify Alzheimer's Disease and Related Syndromes in Administrative Data

BACKGROUND

Administrative data are used in the field of Alzheimer's Disease and Related Syndromes (ADRS), however their performance to identify ADRS is unknown.

OBJECTIVE

i) To develop and validate a model to identify ADRS prevalent cases in French administrative data (SNDS), ii) to identify factors associated with false negatives.

METHODS

Retrospective cohort of subjects ≥ 65 years, living in South-Western France, who attended a memory clinic between April and December 2013. Gold standard for ADRS diagnosis was the memory clinic specialized diagnosis. Memory clinics' data were matched to administrative data (drug reimbursements, diagnoses during hospitalizations, registration with costly chronic conditions). Prediction models were developed for 1-year and 3-year periods of administrative data using multivariable logistic regression models. Overall model performance, discrimination, and calibration were estimated and corrected for optimism by resampling. Youden index was used to define ADRS positivity and to estimate sensitivity, specificity, positive predictive and negative probabilities. Factors associated with false negatives were identified using multivariable logistic regressions.

RESULTS

3360 subjects were studied, 52% diagnosed with ADRS by memory clinics. Prediction model based on age, all-cause hospitalization, registration with ADRS as a chronic condition, number of anti-dementia drugs, mention of ADRS during hospitalizations had good discriminative performance (c-statistic: 0.814, sensitivity: 76.0%, specificity: 74.2% for 2013 data). 419 false negatives (24.0%) were younger, had more often ADRS types other than Alzheimer's disease, moderate forms of ADRS, recent diagnosis, and suffered from other comorbidities than true positives.

CONCLUSION

Administrative data presented acceptable performance for detecting ADRS. External validation studies should be encouraged.

A novel approach for medical research on lymphomas: A study validation of claims-based algorithms to identify incident cases

The use of claims database to study lymphomas in real-life conditions is a crucial issue in the future. In this way, it is essential to develop validated algorithms for the identification of lymphomas in these databases. The aim of this study was to assess the validity of diagnosis codes in the French health insurance database to identify incident cases of lymphomas according to results of a regional cancer registry, as the gold standard.Between 2010 and 2013, incident lymphomas were identified in hospital data through 2 algorithms of selection. The results of the identification process and characteristics of incident lymphomas cases were compared with data from the Tarn Cancer Registry. Each algorithm's performance was assessed by estimating sensitivity, predictive positive value, specificity (SPE), and negative predictive value.During the period, the registry recorded 476 incident cases of lymphomas, of which 52 were Hodgkin lymphomas and 424 non-Hodgkin lymphomas. For corresponding area and period, algorithm 1 provides a number of incident cases close to the Registry, whereas algorithm 2 overestimated the number of incident cases by approximately 30%. Both algorithms were highly specific (SPE = 99.9%) but moderately sensitive. The comparative analysis illustrates that similar distribution and characteristics are observed in both sources.Given these findings, the use of claims database can be consider as a pertinent and powerful tool to conduct medico-economic or pharmacoepidemiological studies in lymphomas.

Reliable assessment of the incidence of childhood autoimmune hemolytic anemia

BACKGROUND

Childhood autoimmune hemolytic anemia (AIHA) is a rare and severe disease characterized by hemolysis and positive direct antiglobulin test (DAT). Few epidemiologic indicators are available for the pediatric population. The objective of our study was to reliably estimate the number of AIHA cases in the French Aquitaine region and the incidence of AIHA in patients under 18 years old.

PROCEDURE

In this retrospective study, the capture-recapture method and log-linear model were used for the period 2000-2008 in the Aquitaine region from the following three data sources for the diagnosis of AIHA: the OBS'CEREVANCE database cohort, positive DAT collected from the regional blood bank database, and the French medico-economic information system.

RESULTS

A list of 281 different patients was obtained after cross-matching the three databases; 44 AIHA cases were identified in the period 2000-2008; and the total number of cases was estimated to be 48 (95% confidence interval [CI]: 45-55). The calculated incidence of the disease was 0.81/100,000 children under 18 years old per year (95% CI 0.76-0.92).

CONCLUSION

Accurate methods are required for estimating the incidence of AIHA in children. Capture-recapture analysis corrects underreporting and provides optimal completeness. This study highlights a possible under diagnosis of this potentially severe disease in various pediatric settings. AIHA incidence may now be compared with the incidences of other hematological diseases and used for clinical or research purposes.

Infections in non-splenectomized persistent or chronic primary immune thrombocytopenia adults: risk factors and vaccination effect

Essentials The risk factors for infection in immune thrombocytopenia are not well known. We conducted a national pharmacoepidemiological study. Pulmonary disease, corticosteroids and rituximab were the main risk factors for infections. Pneumococcal and influenza vaccines were protective against infections.

SUMMARY

Introduction Risk factors for infection and protective effect of vaccines in immune thrombocytopenia (ITP) patients in the era of rituximab therapy are unknown. Objectives To assess the risk factors for serious and non-serious infections (respectively, SIs and NSIs) in non-splenectomized adults treated for persistent or chronic primary ITP, including the effect of pneumococcal and influenza vaccines. Patients/Methods The population was the 2009-2012 FAITH cohort (n = 1805), which is the cohort of all incident (newly diagnosed) primary ITP adults treated > 3 months in France built into the national health insurance database (SNIIRAM). SIs were hospitalizations with any infection as the primary diagnosis code. NSIs were identified using out-of-hospital antibiotic dispensing. Cox models were performed. Results Incidence rates were 6.3/100 patient-years (95% confidence interval [CI], 5.4-7.4) for SIs (lower respiratory tract in 42.8% of the cases) and 100.5/100 patient-years (95% CI, 95.0-106.3) for NSIs. In multivariate analyses, increasing age and chronic pulmonary disease were associated with both SI and NSI occurrence. The hazard ratios (HRs) for corticosteroids and rituximab were, respectively, 3.83 (95% CI, 2.76-5.31) and 2.60 (95% CI, 1.67-4.03) for SIs and 2.46 (95% CI, 2.19-2.76) and 1.49 (95% CI, 1.28-1.74) for NSIs. Pneumococcal vaccine showed a protective effect for both SIs and NSIs (0.38 [95% CI, 0.20-0.73] and 0.52 [95% CI, 0.43-0.65], respectively), as did influenza vaccine (0.42 [95% CI, 0.27-0.64] and 0.49 [95% CI, 0.41-0.59], respectively). Conclusions Chronic pulmonary disease, corticosteroids and rituximab are the main risk factors for infections, whereas pneumococcal and influenza vaccines are protective against SIs and NSIs.