Otago University Reveals Sharp Rise in Sepsis Cases in New Zealand

🩺 Unpacking the Surge: Otago's Landmark Sepsis Study

The University of Otago has delivered a pivotal contribution to public health research with its comprehensive analysis of sepsis trends in Aotearoa New Zealand. This groundbreaking study, led by PhD candidate Sharla McTavish from the Department of Public Health at Otago's Wellington campus, marks the first national examination of long-term epidemiological patterns in sepsis-associated hospitalisations from 2000 to 2019. Published in The Lancet Regional Health – Western Pacific, the research reveals a stark 78% increase in hospital admissions for sepsis, underscoring the growing burden on New Zealand's healthcare system and highlighting persistent inequities among vulnerable populations.

Over the two decades studied, researchers identified 266,105 unique sepsis-associated hospitalisations (SAH), resulting in 27,402 deaths—accounting for nearly 5% of all mortality in the period. While survival rates have improved, the rising incidence demands urgent attention from policymakers, clinicians, and educators in New Zealand's higher education institutions, where future health professionals are trained.

Defining Sepsis: The Life-Threatening Immune Response

Sepsis, often referred to as blood poisoning in lay terms, is a severe medical emergency characterised by the body's dysregulated immune response to an infection. This overreaction triggers widespread inflammation, leading to tissue damage, organ failure, and potentially death if not addressed promptly. The full clinical definition, as per the Sepsis-3 criteria adopted internationally, involves life-threatening organ dysfunction caused by a dysregulated host response to infection.

The process unfolds in stages: an initial infection—commonly from bacteria like Staphylococcus or Streptococcus, but also viruses, fungi, or parasites—escalates when the immune system releases excessive cytokines, causing systemic effects. Early signs include fever, rapid heart rate, and confusion, progressing to septic shock with dangerously low blood pressure. In New Zealand, common entry points are urinary tract infections, pneumonia, and skin infections, particularly in hospital or community settings.

Otago's study emphasises that sepsis is not a single disease but a syndrome affecting anyone, though risk factors amplify vulnerability. Understanding this complexity is crucial for medical students and researchers training at institutions like the University of Otago, where public health curricula integrate real-world data to prepare graduates for frontline challenges.

Statistical Trends: A 78% Rise in Hospital Admissions

The age-standardised incidence rate (ASIR) of sepsis hospitalisations climbed from 217.3 per 100,000 population in 2000 to 386.9 per 100,000 in 2019, reflecting an average annual increase of 4.5%. This surge aligns with global patterns but is pronounced in Aotearoa due to demographic shifts like an ageing population and rising chronic conditions such as diabetes and obesity.

Raw numbers tell a compelling story: annual SAH rose steadily, peaking in the late 2010s. Mortality trends show progress—the age-standardised mortality rate (ASMR) dropped from 37.1 to 31.3 per 100,000, and case fatality risk (CFR) halved from 15.9% to 8.1%. These gains are attributed to better recognition, antibiotics, and intensive care, yet the absolute burden remains heavy.

Data from the study highlights how these trends strain hospital resources, informing resource allocation in university-affiliated teaching hospitals like those partnered with Otago Medical School.

Demographic Disparities: Māori, Pacific Peoples, and Deprivation

Equity gaps are stark: Māori face 1.7 times higher ASIR and 1.6 times higher ASMR than non-Māori, non-Pacific, non-Asian (NMPA) populations, while Pacific peoples experience 2.3 times the hospitalisation rate and 1.7 times the mortality. Residents in the most deprived quintile (NZDep Q5) have twice the risk compared to the least deprived.

• Age extremes: Infants under 1 year (1,340.9/100k ASIR) and those 70+ (1,492.7/100k) bear the heaviest load.
• Gender: Males show 1.28 times higher mortality.
• Social determinants: Overcrowding, multimorbidity, and access barriers exacerbate risks in high-deprivation areas.

Otago researchers link these to upstream factors like poverty and healthcare access, urging culturally responsive interventions—a focus in the university's Māori and Pacific health research programmes.

Otago's Public Health Department: A Hub for Infectious Disease Research

The Department of Public Health at the University of Otago, Wellington, stands at the forefront of New Zealand's response to infectious threats. Home to the Infectious Disease Research group, led by Professor Michael Baker and Dr Amanda Kvalsvig, it fosters interdisciplinary work on pandemics, antimicrobial resistance, and now sepsis epidemiology. This study exemplifies Otago's strength in leveraging national datasets like the National Minimum Dataset for population health insights.

Otago's Wellington campus integrates teaching, research, and policy, training postgraduate students in epidemiology and health equity. The department's collaborative model involves clinicians from Auckland City Hospital and Waikato Hospital, bridging academia and practice.

Spotlight on Key Researchers Driving Change

Sharla McTavish, lead author and Tangata Tiriti PhD candidate, brings fresh perspectives on health inequities. Supervised by Prof Michael Baker—an internationally recognised epidemiologist known for COVID-19 modelling—and Dr Amanda Kvalsvig, expert in outbreak response, the team includes June Atkinson (data analyst), Jane Zhang, and clinicians like Paul Huggan from Sepsis Trust NZ.

These academics mentor the next generation, with PhD programmes emphasising real-world impact. McTavish notes, "Sepsis had a large impact on health and wellbeing... combined with inequalities, the risk increases even more." Such voices shape policy and education at Otago.

Survival Improvements: Treatment Advances and Challenges

Declining CFR reflects better diagnostics like qSOFA scores, bundled care (antibiotics within 1 hour, fluids), and ICU advancements. In NZ, initiatives like Health Quality & Safety Commission's sepsis pathways have contributed, yet only half of patients receive timely treatment.

Challenges persist: antimicrobial resistance, post-sepsis syndrome (fatigue, PTSD in 50% survivors), and ICU pressures. Otago's research baseline will track future gains, informing medical curricula on evidence-based protocols.

Healthcare System Strain and Policy Responses

Sepsis costs NZ millions annually in hospital stays and ACC claims. With 1 in 5 cases needing ICU, and cancer/surgical patients at high risk, early recognition could save lives and resources. Health NZ is advancing e-vitals for deterioration alerts and antimicrobial guidelines.

Sepsis Trust NZ, co-founded by Dr Huggan, pushes for a national action plan covering prevention, surveillance, and survivor support—echoing Otago's recommendations. Minister Simeon Brown has engaged stakeholders post-study release.

Integrating Sepsis into Otago's Medical Education

Otago Medical School's MBChB programme features a spiral curriculum where sepsis is introduced early and revisited with increasing depth. Year 1-2 learners study pathophysiology; clinical years emphasise recognition via simulations and ward rounds at Dunedin Hospital.

Electives in public health expose students to epidemiology like this study, fostering skills in data analysis and equity-focused care. Postgraduate options in the Division of Health Sciences prepare specialists for sepsis research and leadership.

Future Research and Higher Ed Opportunities in NZ

Otago plans longitudinal survivor studies and intervention trials targeting inequities. Collaborations with other unis like Auckland and Massey could expand this. For aspiring researchers, Otago offers funded PhDs in infectious diseases, aligning with Health Research Council priorities.

Prospective students and professionals can explore roles in epidemiology, contributing to NZ's health resilience amid rising antimicrobial threats.

Careers in Public Health: From Otago to Impact

This study spotlights career paths in university research: PhD training leads to policy advising, clinical trials, or academia. Otago's network offers placements at Te Whatu Ora, ideal for med grads pivoting to public health. With sepsis's rising profile, demand grows for experts in surveillance and prevention.

Photo by Artem Beliaikin on Unsplash