University of Otago's Landmark Study on Sepsis Trends
The University of Otago has delivered a pivotal contribution to public health research with a comprehensive analysis of sepsis hospital admissions in Aotearoa New Zealand spanning two decades. Led by PhD candidate Sharla McTavish from the Department of Public Health at Otago's Wellington campus, the study reveals a dramatic 78% increase in age-standardised incidence rates of sepsis-associated hospitalisations, rising from 217.3 per 100,000 population in 2000 to 386.9 in 2019. This population-based research, published in The Lancet Regional Health – Western Pacific, draws on national hospital data to provide the first long-term epidemiological overview, highlighting both the growing burden and evolving survival patterns.
Otago's infectious disease research group, known for its focus on human, animal, and environmental pathogens, underscores the university's role in addressing pressing national health challenges. Professor Michael Baker, a co-author and renowned public health expert, emphasises that many sepsis cases are preventable, urging a strategic public health response to mitigate its impact on Kiwi families.
Understanding Sepsis: A Life-Threatening Response to Infection
Sepsis, often described as blood poisoning or septicaemia in everyday terms, occurs when the body's overwhelming immune response to an infection triggers widespread inflammation, potentially leading to organ failure and death if not treated promptly. It typically starts from common infections like pneumonia, urinary tract infections, or skin wounds, but can escalate rapidly. In New Zealand's context, where an ageing population and rising chronic conditions such as diabetes amplify risks, early recognition is crucial. The condition affects approximately 260,000 hospital admissions over the study period, contributing to 27,402 deaths—nearly 5% of all mortality in the country.
Otago researchers utilised International Classification of Diseases, Tenth Revision (ICD-10) codes from the National Minimum Dataset to identify both explicit sepsis cases and implicit ones involving infection plus organ dysfunction, ensuring a robust methodology that captures the true scope of the problem.
Key Trends: A 78% Surge in Hospital Admissions
Over the 20 years from 2000 to 2019, sepsis hospital admissions showed a consistent upward trajectory, with an average annual percentage change (AAPC) of 4.5% in age-standardised incidence rates. By decade, admissions jumped from 41,683 in 2000-2009 to 93,177 in 2010-2019—a 73.6% increase. While crude numbers of deaths rose slightly by 12.4%, age-standardised mortality rates declined from 37.1 to 31.3 per 100,000, reflecting advances in hospital care.
| Year | ASIR (per 100,000) | ASMR (per 100,000) | CFR (%) |
|---|---|---|---|
| 2000 | 217.3 | 37.1 | 15.9 |
| 2019 | 386.9 | 31.3 | 8.1 |
| Average 2000-2019 | 320.4 | 34.2 | 10.3 |
This table illustrates the stark divergence: rising admissions amid falling fatality risks, particularly for patients over 40, where survival improvements drove the overall decline in case fatality from 15.9% to 8.1%.
Disparities Highlighted: Māori, Pacific Peoples and Deprivation
The study exposes profound inequities. Māori experienced sepsis incidence rates 1.66 times higher and mortality 1.59 times higher than non-Māori/non-Pacific/non-Asian (NMPA) groups. Pacific peoples faced even steeper risks: 2.31 times higher incidence and 1.72 times higher mortality. Residents in the most deprived quintile (NZDep Q5) had nearly double the incidence (1.97x) and mortality (1.95x) compared to the least deprived (Q1). Infants under one year and those over 70 bore the highest burdens, with rates exceeding 1,300 per 100,000 in vulnerable groups.
- Māori and Pacific higher chronic disease prevalence exacerbates risks.
- Household overcrowding, a social determinant, compounds vulnerability.
- Socioeconomic deprivation correlates with delayed access to care.
McTavish notes, “People living with multiple long-term health conditions are at higher risk, and inequalities like overcrowding amplify this further.” These findings align with Otago's broader work on health inequities.
Survival Gains: Advances in Treatment and Recognition
Despite rising admissions, case fatality risk halved, from 15.9% to 8.1%, largely due to better outcomes in older adults. This mirrors global improvements from protocolised care, like timely antibiotics and fluids within the 'golden hour'. In New Zealand, initiatives such as the Health Quality & Safety Commission's sepsis pathways and e-learning modules have contributed, though implementation varies.
Dr Paul Huggan of Sepsis Trust NZ points out that only half of patients receive treatment within three hours, below global benchmarks, underscoring the need for nationwide standardisation.
Otago's Public Health Leadership in Infectious Diseases
The University of Otago's Department of Public Health, particularly its Wellington campus (Ōtakou Whakaihu Waka ki Pōneke), excels in infectious disease epidemiology. This study exemplifies their commitment to using national datasets for policy-relevant insights. Ongoing projects explore sepsis survivors' experiences and ICU disparities, building on prior work like 'Raise the Flag' quality improvement programmes.
Otago's research informs government strategies, positioning the university as a key player in training future public health leaders through PhD programmes and collaborations with iwi like Ngāi Tahu.
Risk Factors Driving the Surge in New Zealand
New Zealand's ageing population, increasing multimorbidity (e.g., diabetes rates up 50% since 2000), and better diagnostic coding explain much of the rise. Antimicrobial resistance, post-flu complications, and social factors like overcrowding in Māori/Pacific households heighten vulnerability. Globally, similar trends occur, but NZ's inequities stand out compared to peers like Australia.
Global Context: NZ Aligns with Rising Burdens
Worldwide, sepsis causes 20 million cases yearly, with incidence rising due to ageing and resistance. NZ's 4.5% AAPC exceeds some high-income countries, but survival gains match trends (e.g., US CFR down to ~10%). Unlike the UK's national action plan, NZ lacks a coordinated strategy, lagging behind 10+ nations committed by 2030.Sepsis Trust NZ's proposed plan offers a blueprint.
Policy Calls: Towards a National Sepsis Action Plan
Researchers and Sepsis Trust NZ advocate a comprehensive plan covering prevention, surveillance, antibiotics stewardship, and survivor support. Health NZ is reviewing the study, advancing e-vitals and guidelines. Ally Hossain stresses economic benefits: reduced ICU stays and ACC costs. Government prioritisation could save millions while addressing inequities.
Prevention Strategies Rooted in Research
Key steps include hand hygiene, wound care, vaccinations, and chronic disease management. Otago-backed tools like early warning scores aid recognition. Community education targets high-risk groups, with iwi-led initiatives promising for Māori health.
- Practice standard precautions in healthcare.
- Promptly treat infections, especially in vulnerable populations.
- Reduce overcrowding through housing policies.
- Invest in antimicrobial stewardship.
Implications for Healthcare Education and Workforce
Otago's findings highlight training needs for nurses, doctors, and public health specialists in sepsis recognition. Universities like Otago offer specialised programmes in epidemiology and Māori health, preparing graduates for roles in prevention. Rising cases strain ICUs, boosting demand for research and clinical staff.
Future Outlook: Research and Action Ahead
As NZ's population ages, sepsis burdens may intensify without intervention. Otago commits to survivor studies and equity-focused surveillance. A national plan could position NZ as a leader, leveraging university expertise for better outcomes.