The burden of city's pain treatment – A longitudinal one year study of two cities via wastewater-based epidemiology

• Published in: Water research (Oxford) Vol. 229; p. 119391
• Main Authors: Kannan, Andrew, Sims, Natalie, Hold, Angus J., Jagadeesan, Kishore, Standerwick, Richard, Barden, Ruth, Kasprzyk-Hordern, Barbara
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.02.2023
• Subjects: acetaminophen; Analgesics; Anti-Inflammatory Agents, Non-Steroidal - therapeutic use; Chemical mining; Chronic Pain; Cities; England; epidemiology; excretion; health services; Human exposure; Humans; Longitudinal Studies; metabolism; metabolites; NSAIDs; oral administration; Pain; Pharmaceutical Preparations - analysis; population size; seasonal variation; State Medicine; topical application; wastewater; Wastewater-Based Epidemiological Monitoring; Wastewater-based epidemiology; water; Water fingerprinting; WBE; England; Chemical mining; Pain; Water fingerprinting; Analgesics; NSAIDs; Wastewater-based epidemiology; Human exposure; WBE
• ISSN: 0043-1354; 1879-2448; 1879-2448
• DOI: 10.1016/j.watres.2022.119391

•City's pain treatment in a 13-month intercity longitudinal study estimated using WBE.•WBE triangulated with per postcode National Health Service (NHS) prescription data.•Strong seasonal patterns of short pain medications vs chronic pain treatment observed.•Topical (non-metabolic) application/down-the-drain disposal of pharmaceuticals observed.•Population size is the main driver of pharma loads in wastewater. This paper explores Wastewater-Based Epidemiology (WBE) as a tool enabling understanding of city's pain treatment in an intercity longitudinal study. An intensive 13-month monitoring programme was undertaken in two adjacent urban areas in South-West England: a small commuter town Keynsham and the city of Bath (>180 samples collected). The study has shown a great potential of using triangulated WBE and National health Service (NHS) prescription data in understanding pain treatment in two contrasting communities with strong apparent seasonal patterns of short pain medications vs chronic pain treatment as well as the type of treatment used (e.g. oral vs topical). Community-wide usage of Non-Steroidal Anti-inflammatory Drugs (NSAIDs) and paracetamol in the intercity study is population size and season driven with the highest usage recorded in winter months. This contrasts with other pain pharmaceuticals, especially those used for chronic pain, where no/limited seasonal usage was recorded. Unmetabolized NSAIDs are, to a large extent, directly disposed of into the sewerage system bypassing metabolism due to their topical application. This is particularly apparent in winter months with naproxen showing the highest seasonal variability. Pharma/met (ratio of pharmaceutical and its metabolite concentration) analysis allows for tracking topical (non-metabolic) application/down-the-drain disposal of pharmaceuticals with frequent instances of direct disposal of NSAIDs into the sewerage system observed. Normalisation of pharma markers to population size shows comparable estimates of pharma usage in the two cities confirming population as the main driver of pharma loads in wastewater. Variable application patterns of pain pharmaceuticals make back-calculation of intake more convoluted. Intake calculated using percentage excretion of parent NSAIDs will likely lead to overestimation, as it is assumed that NSAIDs are subject to extensive metabolism (this is not the case for topical applications). Intake calculated using percentage excretion of metabolites (or parent compound) as consumption markers leads to underestimation of NSAIDs usage due to contributions from topical application not being accounted for. Prescription data indicates cumulative internal and topical usage, but the data ignores large proportion of over-the-counter usage. Therefore, we have proposed a combined approach allowing for estimation of total usage including, and differentiating between, topical application and oral administration.