26th October 2018, Volume 131 Number 1484

Jerome Ng, Penny Andrew, Paul Muir, Monique Greene, Sabitha Mohan, Jacqui Knight, Phil Hider, Peter Davis, Mary Seddon, Shane Scahill, Jeff Harrison, Lifeng Zhou, Vanessa Selak, Carlene Lawes, Geetha Galgali, Joanna Broad, Marilyn Crawley, Wynn Pevreal, Neil Houston, Tamzin Brott, David Ryan, Jocelyn Peach, Andrew Brant, Dale Bramley

Adverse drug events (ADEs) account for a significant proportion of all iatrogenic harm (up to 38%)1 and improvement initiatives have been introduced into New Zealand hospitals to prevent them.2 The…

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The routine measurement of adverse drug events (ADE) is important for monitoring and informing improvement, but current detection tools are manual and too resource intensive. Our research, for the first time, shows ADEs can be reliably and sustainably measured using clinical coding surveillance (CCS). Using CCS, almost 12,000 ADEs over two years were detected in hospitalised patients. Most ADEs originated from the community setting.



To explore the feasibility and reliability of Clinical Coding Surveillance (CCS) for the routine monitoring of Adverse Drug Events (ADE) and describe the characteristics of harm identified through this approach in a large district health board (DHB).


All hospital admissions at Waitemata DHB from 2015 to 2016 with an ADE-related ICD10-AM code of Y40-Y59, X40-X49 or T36-T50 were extracted from clinical coded data. The data was analysed using descriptive statistics, statistical process control and Pareto charts. Two clinicians assessed a random sample of 140 ADEs for their accuracy against what was clinically documented in medical records.


A total of 11,999 ADEs were identified in 244,992 admissions (4.9 ADEs per 100 admissions). ADEs were more prevalent in older adults and associated with longer average length of stays and medicines such as analgesics, antibiotics, anticoagulants and diuretics. Only 2,164 (18%) of ADEs were classified as originating within hospital. Of ADEs originating outside of the hospital, the main causes were poisoning by psychotropics, anti-epileptics and anti-parkinsonism agents and non-opioid analgesics. Clinicians agreed that 91% of ADE positive admissions were accurately classified as per clinical documentation.


CCS is a feasible and reliable approach for the routine monitoring of ADEs in hospitals.

Author Information

Jerome Ng, Lead Advisor, Improvement, Research & Informatics, Institute for Innovation and Improvement (i3), Waitemata DHB, Auckland; Penny Andrew, Director, Institute for Innovation and Improvement (i3), Waitemata DHB, Auckland; Paul Muir, Medical Fellow, Planning, Funding and Outcomes, Waitemata DHB, Auckland; Monique Greene, Information Analyst, Institute for Innovation and Improvement (i3), Waitemata DHB, Auckland; Sabitha Mohan, Clinical Coding Auditor, Health Information Group, Waitemata DHB, Auckland; Jacqui Knight, Clinical Coding Team Leader, Health Information Group, Waitemata DHB, Auckland; Phil Hider, Senior Lecturer, Department of Population Health, University of Otago, Christchurch; Peter Davis, Professor, Centre of Methods and Policy Application in the Social Sciences (COMPASS), University of Auckland, Auckland;
Mary Seddon, Independent Consultant, Seddon Healthcare Quality, Auckland;
Shane Scahill, Senior Lecturer, School of Management, Massey University, Auckland;
Jeff Harrison, Associate Professor, School of Pharmacy, University of Auckland, Auckland;
Lifeng Zhou, Chief Advisor for Asian International Collaboration, Waitemata District Health Board, Auckland; Vanessa Selak, Senior Lecturer, School of Population Health, University of Auckland, Auckland; Carlene Lawes, Public Health Physician (Surgical), Institute for Innovation and Improvement (i3), Waitemata DHB, Auckland; Geetha Galgali, Public Health Physician (Maternity), Child, Women and Family, Waitemata DHB, Auckland; Joanna Broad, Senior Research Fellow, Department of Geriatric Medicine, University of Auckland, Auckland; Marilyn Crawley, Chief Pharmacist, Pharmacy Department, Waitemata DHB, Auckland; Wynn Pevreal, Medication Safety Pharmacist, Pharmacy Department, Waitemata DHB, Auckland (Died 24 April 2018); Neil Houston, Clinical Director for Safety and Quality in Primary Care, Waitemata DHB, Auckland; Tamzin Brott, Executive Director—Allied Health, Scientific & Technical Professions, Waitemata DHB, Auckland;
David Ryan, Information Systems Change Manager, Health Information Group, Waitemata DHB, Auckland; Jocelyn Peach, Director of Nursing and Midwifery, Waitemata DHB, Auckland;
Andrew Brant, Chief Medical Officer, Waitemata DHB, Auckland; Dale Bramley, Chief Executive Officer, Waitemata DHB, Auckland.


We gratefully acknowledge the following people for their support and advice: Ross S, Wallace I, Gilmour K, Farmer E, Wood P, Doogue M, Wilkinson J, Young M, Li Y, Hamblin R and Armstrong D.


Dr Jerome Ng, Institute for Innovation and Improvement, Waitemata DHB West Wing, Taharoto Building (Building 1), North Shore Hospital Site, Takapuna, Private Bag 93-503, Auckland 0740.

Correspondence Email


Competing Interests



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