Data Resource profile: Medicines in Acute and Chronic Care in Scotland (MACCS)

The Medicines in Acute and Chronic Care in Scotland (MACCS) resource is a curated, national-level dataset that integrates and harmonizes diverse prescribing and clinical records from multiple healthcare settings to enable robust, longitudinal research on medicine exposure and health outcomes within the NHS Scotland system.

The Gist

Imagine Scotland's healthcare system as a massive, bustling library. For years, the books (patient records) have been stored in different rooms: one room for medicines given at home, another for pills picked up at local pharmacies, and a third for treatments given in hospitals. While each room is well-organized on its own, trying to find a specific story about a patient's journey across all these rooms was like trying to read a novel where the pages were scattered across three different buildings. You'd have to run back and forth, and you might miss crucial plot twists.

The MACCS Project: The Ultimate "All-in-One" Storybook

The paper you read introduces MACCS (Medicines in Acute and Chronic Care in Scotland). Think of MACCS as a brilliant librarian who decided to gather all those scattered pages, sort them out, and bind them into a single, massive, easy-to-read storybook for every adult in Scotland.

Here is how it works, broken down into simple concepts:

1. The Problem: The "Jigsaw Puzzle" in Different Boxes

Before MACCS, if a researcher wanted to study how a specific medicine affected a patient's heart over ten years, they had to:

• Go to the Pharmacy Box to see what pills were bought.
• Go to the Hospital Box to see what was injected or administered.
• Go to the Lab Box to check blood test results.
• Go to the Death Records Box to see if the patient passed away.

Doing this manually for millions of people was impossible. The data was there, but it was fragmented, like a giant jigsaw puzzle where the pieces were locked in separate boxes.

2. The Solution: The "Master Connector"

MACCS acts as the Master Connector. It uses a unique "ID card" (called the CHI number) that every Scottish resident has. It takes the puzzle pieces from the pharmacy, hospital, and home-care boxes and snaps them together perfectly.

• What it connects: It links medicine records with hospital visits, cancer registries, kidney disease records, blood test results, and even death records.
• Who it covers: It covers about 4.6 million adults (everyone 18 and older) who have received medicine in Scotland since 2010. That's almost the entire adult population!

3. The "Safe Room" (Trusted Research Environment)

You might wonder, "Can I just download this book?" The answer is no. Because these are real people's private medical stories, they are kept in a digital "Safe Room" (called a Trusted Research Environment).

• How it works: Imagine a high-security vault. Researchers can't take the books out. Instead, they are allowed to enter the vault, sit at a computer, and read the stories or run their own analysis.
• The Guard: A strict security team (governance) watches over the vault to ensure no one steals a page or sees a name. Only approved researchers with a valid "ticket" (ethical approval) can enter.

4. Why is this a Big Deal? (The Superpowers)

By having all this data in one place, MACCS gives researchers "superpowers":

• The Time-Traveler: Researchers can watch a patient's story unfold over years. They can see: Did taking this pill in 2015 lead to a hospital visit in 2020?
• The Detective: They can spot patterns that were previously invisible. For example, they can find out if a specific high-dose antipsychotic drug is causing more hospital visits for certain groups of people.
• The Safety Inspector: It helps the government and drug companies check if new medicines are safe for the whole population, not just a small group of volunteers in a trial.

5. Real-World Examples

The paper mentions a few "detective stories" currently being solved with MACCS:

• The Antipsychotic Mystery: Researchers are looking at why some hospital patients are given very high doses of mental health medication and checking if it leads to bad outcomes.
• The "Super-Drug" Watch: They are tracking powerful new drugs (like biologics) to see if they cause rare but serious side effects like heart attacks or infections.
• The Blood Thinner Test: They are trying to predict which patients taking blood thinners might have a dangerous bleed, so doctors can treat them more carefully.

6. The Catch (Limitations)

Even the best storybook has some missing pages.

• Missing "Why": Sometimes the data tells us what medicine was given, but not why the doctor chose it (the clinical reason).
• Time Lag: It takes a little time to clean and organize the data, so it's not always "live" (real-time) like a stock market ticker.
• Adults Only: Currently, this storybook only covers adults (18+), so children's stories aren't in here yet.

The Bottom Line

MACCS is like a massive, secure, digital time machine for Scotland's health. It turns millions of scattered, confusing medical records into a clear, connected story. This allows scientists to learn from the past to make better decisions for the future, ensuring that medicines are safer and healthcare is better for everyone in Scotland.

Technical Summary

1. Problem Statement

Scotland possesses high-quality, comprehensive routinely collected prescribing and medicine-related data. However, these data are fragmented across multiple healthcare settings (primary care, secondary care/hospitals, and home care) and stored in distinct, complex source systems not optimized for longitudinal or outcomes-focused research.

• Key Challenges:
  • Data Silos: Medicines data is stored separately from clinical outcomes (hospital admissions, lab results, mortality).
  • Lack of Standardization: Inconsistent representations of medicine exposure across different systems hinder cross-setting analysis.
  • Research Barriers: The fragmentation prevents robust population-scale studies on medicine utilization, adherence, and safety outcomes across the entire healthcare pathway.
  • Access Complexity: Researchers historically faced the burden of navigating multiple dataset-specific approvals to link data.

2. Methodology

The MACCS resource was established in 2025 as a national, individual-level, curated dataset designed to bridge these gaps.

• Data Sources & Integration:
  • Core Medicine Datasets: Integrates three primary sources:
    • Prescribing Information System (PIS): Community pharmacy dispensing (since 04/2009).
    • Hospital Electronic Prescribing and Medicines Administration (HEPMA): Inpatient administration (since 07/2022).
    • Home Care Medicines (HCM): Specialist medicines delivered to homes (since 01/2019).
  • Linked Clinical Datasets: Linked at the individual level via the unique NHS Scotland identifier (Community Health Index - CHI) to 11 other national records, including:
    • Scottish Morbidity Records (SMR00/01/02/04/06) for outpatient, inpatient, maternity, mental health, and cancer data.
    • Scottish Renal Registry (SRR).
    • Scottish Care Information (SCI) Store for laboratory biochemistry/haematology.
    • Electronic Communication of Surveillance Scotland (ECOSS) for microbiology.
    • National Records of Scotland (NRS) for mortality.
    • Scottish Intensive Care Society Audit Group (SICSAG).
• Population Cohort:
  • Inclusion Criteria: Adults (≥18 years) residing in Scotland who have received at least one prescription medicine since 2010.
  • Coverage: Approximately 4.6 million individuals (covering ~87% of the Scottish population).
• Data Processing & Architecture:
  • Environment: Hosted within the National Safe Haven (NSH) and accessed via Trusted Research Environments (TREs).
  • Pipeline: Source extracts are ingested into a controlled staging layer for quality checks. Data is then linked, cleaned, and harmonized using a structured database schema.
  • Standardization: Variables are harmonized using consistent naming conventions. Coding systems include British National Formulary (BNF), Dictionary of Medicines & Devices (dm+d), Anatomical Therapeutic Chemical (ATC) classification, and ICD-10.
  • Updates: The resource is updated annually with regular data extractions to support longitudinal analysis.

3. Key Contributions

• Unified Resource: MACCS is the first resource to provide pre-linked, analysis-ready medicines data across primary, secondary, and home care settings in Scotland.
• Longitudinal Capability: Enables follow-up of the adult population since 2010, supporting time-to-event studies, look-back periods, and trend analysis.
• Streamlined Governance: Researchers apply once for access to the pre-linked resource via the Public Benefit and Privacy Panel for Health and Social Care (PBPP-HSC), eliminating the need for multiple dataset-specific approvals.
• Comprehensive Clinical Context: Beyond prescribing, it links to critical outcomes including cancer registries, renal data, microbiology surveillance, and mortality, allowing for robust pharmacoepidemiological studies.

4. Results (Current Status & Applications)

• Data Availability: As of February 2026, the resource covers ~4.6 million individuals with data ranging from 2004 (registries) to 2025 (current prescribing).
• Active Research Applications:
  • Antipsychotic Safety: A study evaluating high-dose antipsychotic prescribing in hospitals, linking exposure to clinical outcomes, adverse events, and mortality to inform Clinical Decision Support (CDS) tools.
  • Pharmacovigilance: A feasibility study commissioned by the MHRA monitoring safety signals (infections, cardiovascular events, malignancies) for targeted immune-modifying therapies (biologics and JAK inhibitors).
  • Predictive Modeling: A planned study to validate a risk prediction model for severe bleeding in patients on Direct Oral Anticoagulants (DOACs).
  • Post-COVID Analysis: Investigating long-term psychiatric medication use following COVID-19 infection.

5. Significance

• Scientific Impact: MACCS significantly enhances the capacity for high-quality, population-scale research by removing technical barriers to data linkage. It supports diverse methodologies, including advanced statistics and Artificial Intelligence (AI).
• Policy & Clinical Practice: The resource facilitates the evaluation of real-world prescribing practices, patient adherence, and long-term safety, directly informing clinical guidelines, health policy, and medicines optimization strategies in Scotland.
• Limitations & Future Work:
  • Limitations: Inherent to administrative data (e.g., lack of clinical indication in prescribing records, approximated dates in home care, time lags for data availability). Currently restricted to adults (≥18).
  • Future Expansion: Plans to integrate unscheduled care data (Emergency Departments, GP out-of-hours) and primary care GP records.
• Accessibility: While not open-access due to privacy, it offers a streamlined, secure access model for approved researchers, fostering international collaboration through UK-based partners.

In conclusion, MACCS represents a transformative infrastructure for medicines research in Scotland, converting fragmented administrative data into a cohesive, longitudinal asset capable of driving evidence-based improvements in patient care and public health policy.