Analysis of Medication Possession Ratio for Improved Blood Pressure Control

Analysis of Medication Possession Ratio for Improved Blood Pressure Control Thusitha Mabotuwana With: Jim Warren, Rekha Gaikwad, John Kennelly, Timothy Kenealy 16 October 2008

CVD/Hypertension
In 2007 over 38% of deaths (i.e. >233,000 deaths!) in the UK were due to a cardiovascular disease (CVD) related problem
In NZ, CVD accounts for 40% of all deaths
In 2005, CVD related cost burden to EU economy €169 billion/yr
Hypertension is a significant risk factor of CVD
The risk of CVD beginning at 115/75 mmHg doubles with each increment of 20/10 mmHg;
Even the slightest improvement in the management of hypertensive patients can have significant cost and health benefits
S. Allender, V. Peto, P. Scarborough, A. Boxer, and M. Rayner, "Mortality," in Coronary heart disease statistics London: British Heart Foundation (BHF), 2007, p. 12.

The opportunity
New Zealand in top tier on use of computing in General Practice medicine (near 100%)
US and Canada well lagging, incidentally
Denmark is a particular leader
Prescribing and results of tests ordered systemically present in Practice Management System (PMS)
Anecdotally, the quality of the record continues to improve on more ‘voluntary’ fields (e.g., Blood Pressures [BPs], diagnoses)
So the PMS data should tell us a lot about what’s going on in CVD risk management
Schoen C et al. On the front lines of care: primary care doctors' office systems, experiences, and views in seven countries.. Health Aff (Millwood). 2006 Nov–Dec;25(6):w555-71.

What we did
Collaborated with a (largely Pacific) general practice in West Auckland
Worked with a ‘panel’ – practice manager, two practice nurses, two GPs of the practice along with an external GP.
Identified some important explicit quality audit criteria they thought were important
Developed a ‘system’ that could answer GP queries

Identified Criteria Persistence of treatment – No large gaps in therapy?

Identified Criteria Measurement related – Have we recorded BP into the PMS record

Identified Criteria Achieving targets – Patients not taking ‘too long’ to achieve target BP

Identified Criteria Compelling indications

Identified Criteria
Management of other complications
E.g., renal function and gout issues

Current focus

Adherence to medication
Generally defined as the extent to which patients take medications as prescribed by their health care providers
We all know adherence to medication is important to achieve the full benefit of the many effective medications – patients need to follow prescribed treatment regimens reasonably closely.

How should we measure adherence?
No existing gold standard for measuring adherence
Medication Possession Ratio (MPR) is widely used as a measure of adherence to long-term medication, such as AHT medication
Andrade SE, Kahler KH, Frech F, Chan KA: Methods for evaluation of medication adherence and persistence using automated databases . Pharmacoepidemiology and drug safety 2006, 15 (8):565-574; discussion 575-567 Number of days supply held during evaluation period Number of days in evaluation period X 100

MPR calculation considerations
We consider only that portion which overlaps with evaluation period
Evaluation Period (EP) (12 months) Run-in Period (6 months) AHT Pr1 AHT Pr2 AHT Pr3 AHT Pr4

Methods
So we know what we want, but how do we go about doing it?

Ontology development in Protégé-OWL
Why use an ontology?
Can use domain level concepts instead of system specific details.
Easy to visualise the hierarchy

Data extract
We extracted EMR data from the practice’s PMS
11393 patients (demographics – age in years, gender, ethnicity as coded in the PMS)
66188 dates of encounters
31716 classifications (also referred to as diagnoses)
60721 prescriptions
11865 blood pressure measurements
Lab test results relevant to AHT
3411 creatinine measurements
1675 uric acid measurements
3322 eGFR measurements
1550 albumin creatinine ratios
2661 HbA1Cs
1558 microalbumin measurements

Patient Identifiers Patient Lab Tests Patient BPs Patient Prescriptions Patient Classifications Selected Patient Patient MPRs

Relationship of Adherence to BP Control N = 280 n (HT only) = 157 n (HT & DM) = 123 No surprise here – need to work on concordance Hmm… could be that the therapy isn’t aggressive enough OR The patient is picking up the scripts but adherence breaks down later (e.g., not filling the script or not taking the medication as directed) Controlled SBP (SBP  140 or SBP  130 if DM present) Uncontrolled SBP Adherent (MPR  80%) 86 87 Non-adherent 35 72 Odds of control improves signifi-cantly

Medication lapse as a measure of adherence Can define in terms of one medication class, or all antihypertensive medication classes Results in some fiendish SQL! “ HT patients with a lapse in AHT for over 30 days with lapse occurring any time with an overlap with EP” – 1 st criterion

Adapted Gantt chart in MS Excel Regular lapses – probably frequently misses pills, and/or maybe takes a long while to come back to GP once run out 46 day lapse 33 day lapse 40 day ongoing lapse 24 day lapse

A more interactive tool

A more interactive tool – combination drugs Combination drugs

Constrained user interface for query generation

Key messages
- Adherence to prescribed medication is important for lowering SBP
- PMS data can be used to identify chronic patients whose clinical outcomes can be improved (using explicit quality indicators)

Contact, Further Reading
Thusitha Mabotuwana
[email_address]
A similar study done in Australia with similar goals and methods:
Gadzhanova S et al. ‘Developing high-specificity anti-hypertensive alerts by therapeutic state analysis of electronic prescribing records,’ Journal of the American Medical Informatics Association 14(1): 100-9, 2007.
Methods/results for the recent study:
Warren J et al. ‘ Utilising Practice Management System Data for Quality Improvement in Use of Blood Pressure Lowering Medications in General Practice ,’ New Zealand Medical journal (NZMJ) , 2008. Accepted for publication
Opinion/review piece:
Warren J, ‘General Practice EMRs: What they can tell us, and how,’ Health Care and Informatics Review Online , December 2007

Generic name Multiple ways of coding drugs

Core part of the query required to implement the criteria For display purposes

Some Results on MPR and Lapse 80% MPR is most common threshold in adherence literature

UML of Criteria…

We're not alone in looking at either hypertension or the temporal nature of clinical data…
ATHENA DSS
Used at VA
Provides patient specific recommendations (primary/drug) at the point of care based on a specific guideline
Expert clinicians maintain hypertension knowledge base using Protégé
Not so much on running specific queries to identify patient cohorts for intervention
No active development work done on the GUI

Asbru/Asgaard
Task-specific and intention-based plan representation language
Care provider actions are recorded, observed and abstracted over time and critiqued based on intention of underlying plan (ie temporal patterns to maintain, achieve or avoid)
Full support requires explicit representation of intentions
Requires knowledge of domain-specific plan-effects and revision strategies

IDAN/KNAVE II
A conceptual and computational framework for temporal abstraction, visualisation, and exploration of multiple levels of temporal abstractions
Query, visualization and exploration operators are domain independent, but terms and relations specific to each (e.g., medical) domain
Uses standard medical terminology standards (ICD-9, SNOMED, LOINC)
Not used for auditing or identifying cohorts of patients for follow-up, but still very relevant

Process overview OWL ontology in Protégé-OWL (without instances) Generation of high level Java classes using the Protégé-OWL ‘code-generation’ utility (classes based on the Protégé-OWL API Commercial PMS Data extraction using ad-hoc type queries Population of local database with extracted data Generic Java classes representing ontology concepts (not bound to any specific API) Mapping from generic concepts to Protégé-OWL representation using Java pre-processor engine Populated OWL ontology in Protégé-OWL

Temporal issues

Comparison with Quality and Outcomes Framework (QOF)
Our criteria include identifying patients who need a follow-up (eg: “A lapse in AHT >30 days” criterion) which is required for sound adherence
QOF DM15 indicator is “…patients with diabetes…who are treated with ACE inhibitors (or A2 antagonists)” but what is treated with without an EP?
DM 12. The percentage of patients with diabetes in whom the last blood pressure is 145/85 or less
BP 5. The percentage of patients with hypertension in whom the last blood pressure (measured in the previous 9 months) is 150/90 or less

Measures of MPR

Querying for “HT patients with a lapse in AHT for over 30 days with lapse occurring any time with an overlap with EP” Patient Classification details Lapse in, from Lapse to Duration

Analysis of Medication Possession Ratio for Improved Blood Pressure Control

by Health Informatics New Zealand on Nov 02, 2008

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Analysis of Medication Possession Ratio for Improved Blood Pressure Control — Presentation Transcript