The kidneys help control the body's acid level by removing acid from the blood and excreting it into the urine. Distal renal tubular acidosis (dRTA) is a rare, chronic, underestimated and debilitating disease, with severe long term consequences, especially on kidney and bones. It is caused by a defect in the kidney tubes that causes acid to build up in the blood.
The main objective of this study is to analyse health data of patients with dRTA to better understand the resource consumptions attributable to this rare disease by comparing with a group of patients without this condition but with similar socio-demographic and clinical characteristics such as age, gender and existing chronic diseases. This will include use of specialist visits, general practitioner visits, accident and emergency visits, hospital outpatient visits, hospital admissions and medications.
We will also measure the risk associated with the disease of death and of being hospitalised for causes, potentially related to the disease, such as hearing problems, renal conditions, kidney stones.
Since there is currently no specific treatment for distal renal tubular acidosis, our findings are expected to indicate the high burden of the disease and the need in this population. This would inform health care organisations as a whole and potentially specialist and general practitioners.
This study is a non-interventional retrospective study evaluating the healthcare resource utilisation and clinical outcomes of patients with diagnosed or suspected dRTA in the United Kingdom, using the Clinical Practice Research Datalink (CPRD) GOLD and Hospital Episode Statistics (HES) databases.
The primary analyses will consist in estimating the difference in healthcare resource utilisation (HCRU) between patients with dRTA and patients without dTRA, over the past 10 years [1 January 2010 31 December 2020], overall, in adult and in paediatric patients. Healthcare resource categories of interest will be hospital admissions (number and length of stays), outpatient hospital visits, referrals, GP attendances/nursing interactions, accident & emergency (A&E) attendances and medication
Unadjusted and adjusted incidence rate ratios and mean differences in number of HCRU events will be estimated using adjusted negative binomial regression models. Unadjusted and adjusted attributable risk of HCRU events will be estimated using Cox proportional hazards regression models.
In order to eliminate the impact of confounding parameters, patients without dRTA will be defined and selected using a matching process to ensure a balanced comparison between the two cohorts. A propensity score matching is anticipated but other methods will be also considered.
Secondary objectives will consist of describing and comparing health care utilisation, risk of death and risk of hospitalisations due to specific causes, i.e. renal conditions, hearing difficulties, osteoskeletal conditions, kidney stones and hypokalaemia/hyperkalaemia, between patients with dRTA and matched patients without dRTA, considering the whole patients follow-up in CPRD data.
With these comparisons, the researchers hope to quantify the incremental economic and complication burden that dRTA poses to the English NHS.
Primary outcomes:
Healthcare resource use attributable to dRTA:
o Incidence rate ratio of/difference in number of inpatient admissions (for all causes), A&E attendances (for all causes), hospital outpatient visits (for all causes), GP attendances/nursing interactions, referrals, medications between patients with dRTA and patients without dRTA;
o Difference in length of stays between patients with dRTA and patients without dRTA;
o Attributable risk (hazard ratio) of occurrence of inpatient admissions (for all causes), accident & emergency attendances (for all causes), hospital outpatient visits (for all causes), referrals between patients with dRTA and patients without dRTA;
Secondary outcomes:
Healthcare resource use in each group:
o Number of inpatient admissions, hospital outpatient visits, A&E attendances, GP attendances/nursing interactions, referrals, medications;
o Incidence rate of inpatient admissions, hospital outpatient visits, A&E attendances, referrals;
Attributable risk (hazard ratio) of mortality [all-causes], risk of specific cause-related hospitalisation, by specific cause: renal & osteoskeletal conditions, kidney stones, hearing problems, hyperkalaemia/hypokalaemia attributable to dRTA (vs. patients without dRTA);
Patient Demographics (e.g. age, sex, Charlson Comorbidity Index [or an alternative comorbidity index], polypharmacy, follow-up duration, underlying conditions including Sjögren syndrome, systemic lupus erythematosus, sickle cell anaemia, chronic obstructive uropathy, or post-renal transplantation...)
FLORENT Guelfucci - Chief Investigator - Syneos Health Commercial France SARL
FLORENT Guelfucci - Corresponding Applicant - Syneos Health Commercial France SARL
Catherine Martre - Collaborator - Advicenne
David Game - Collaborator - Guy's & St Thomas' NHS Foundation Trust
Florence Bianic - Collaborator - Syneos Health Consulting Inc (formerly inVentiv)
HES Accident and Emergency;HES Admitted Patient Care;HES Outpatient;ONS Death Registration Data;Practice Level Index of Multiple Deprivation