title: Chronic Pain: How Challenging Are DDIs in the Analgesic Treatment of Inpatients with Multiple Chronic Conditions?
abstract: BACKGROUND
  Chronic pain is common in multimorbid patients. However, little is known about the implications of chronic pain and analgesic treatment on multimorbid patients. This study aimed to assess chronic pain therapy with regard to the interaction potential in a sample of inpatients with multiple chronic conditions.
  
  
  RESULTS
  We conducted a retrospective study with all multimorbid inpatients aged ≥18 years admitted to the Department of Internal Medicine of University Hospital Zurich in 2011 (n = 1,039 patients). Data were extracted from the electronic health records and reviewed. We identified 433 hospitalizations of patients with chronic pain and analyzed their combinations of chronic conditions (multimorbidity). We then classified all analgesic prescriptions according to the World Health Organization (WHO) analgesic ladder. Furthermore, we used a Swiss drug-drug interactions knowledge base to identify potential interactions between opioids and other drug classes, in particular coanalgesics and other concomitant drugs. Chronic pain was present in 38% of patients with multimorbidity. On average, patients with chronic pain were aged 65.7 years and had a mean number of 6.6 diagnoses. Hypertension was the most common chronic condition. Chronic back pain was the most common painful condition. Almost 90% of patients were exposed to polypharmacotherapy. Of the chronic pain patients, 71.1% received opioids for moderate to severe pain, 43.4% received coanalgesics. We identified 3,186 potential drug-drug interactions, with 17% classified between analgesics (without coanalgesics).
  
  
  CONCLUSIONS
  Analgesic drugs-related DDIs, in particular opioids, in multimorbid patients are often complex and difficult to assess by using DDI knowledge bases alone. Drug-multimorbidity interactions are not sufficiently investigated and understood. Today, the scientific literature is scarce for chronic pain in combination with multiple coexisting medical conditions and medication regimens. Our work may provide useful information to enable further investigations in multimorbidity research within the scope of potential interactions and chronic pain.
authors.affiliation: Department of Internal Medicine, University Hospital Zurich, Zurich, Switzerland.|Center of Competence Multimorbidity, University of Zurich, Zurich, Switzerland.
authors.forename: Klarissa
authors.initials: K
authors.lastname: Siebenhuener
authors.affiliation: Research Center for Medical Informatics, Directorate of Research and Education, University Hospital Zurich, Zurich, Switzerland.
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Eschmann
authors.affiliation: Department of Internal Medicine, University Hospital Zurich, Zurich, Switzerland.
authors.forename: Alexander
authors.initials: A
authors.lastname: Kienast
authors.affiliation: Maennedorf Hospital, Department of Internal Medicine, Canton Zurich, Switzerland.
authors.forename: Dominik
authors.initials: D
authors.lastname: Schneider
authors.affiliation: Horten Center, University Hospital Zurich, Zurich, Switzerland.
authors.forename: Christoph E
authors.initials: CE
authors.lastname: Minder
authors.affiliation: Center of Competence Multimorbidity, University of Zurich, Zurich, Switzerland.|Institute of Complementary and Integrative Medicine, University Hospital Zurich, Zurich, Switzerland.
authors.forename: Reinhard
authors.initials: R
authors.lastname: Saller
authors.affiliation: Center of Competence Multimorbidity, University of Zurich, Zurich, Switzerland.|Cantonal Hospital, Internal Medicine, Olten, Switzerland.
authors.forename: Lukas
authors.initials: L
authors.lastname: Zimmerli
authors.affiliation: Research Center for Medical Informatics, Directorate of Research and Education, University Hospital Zurich, Zurich, Switzerland.
authors.forename: Jürg
authors.initials: J
authors.lastname: Blaser
authors.affiliation: Department of Internal Medicine, University Hospital Zurich, Zurich, Switzerland.|Center of Competence Multimorbidity, University of Zurich, Zurich, Switzerland.|University Research Priority Program 'Dynamics of Healthy Aging,' University of Zurich, Zurich, Switzerland.
authors.forename: Edouard
authors.initials: E
authors.lastname: Battegay
authors.affiliation: Department of Internal Medicine, University Hospital Zurich, Zurich, Switzerland.|Center of Competence Multimorbidity, University of Zurich, Zurich, Switzerland.
authors.forename: Barbara M
authors.identifier: http://orcid.org/0000-0001-6929-3145
authors.initials: BM
authors.lastname: Holzer
mesh_terms: D000700:Analgesics / Q000627:therapeutic use*; D000701:Analgesics, Opioid / Q000009:adverse effects / Q000627:therapeutic use; D059350:Chronic Pain / Q000188:drug therapy*; D003710:Demography; D004347:Drug Interactions; D011307:Drug Prescriptions; D006748:Hospital Departments; D006801:Humans; D007297:Inpatients; D007388:Internal Medicine; D000071069:Multiple Chronic Conditions / Q000188:drug therapy*; D014944:World Health Organization
chemical_list: D000700:Analgesics; D000701:Analgesics, Opioid