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Serum creatinine trajectories in real-world hospitalized patients: clinical context and short-term mortality
  1. Olga Laszczyńska1,
  2. Milton Severo1,2,
  3. Joana Mascarenhas1,3,
  4. José Artur Paiva4,5,
  5. Ana Azevedo1,2,6
  1. 1EPIUnit, Instituto de Saúde Pública da Universidade do Porto, Porto, Portugal
  2. 2Departamento de Ciências da Saúde Pública e Forenses e Educação Médica, Faculdade de Medicina da Universidade do Porto, Porto, Portugal
  3. 3Serviço de Medicina Interna, Centro Hospitalar Vila Nova de Gaia Espinho, Vila Nova de Gaia, Portugal
  4. 4Serviço de Medicina Intensiva, Centro Hospitalar Universitário de São João, Porto, Portugal
  5. 5Faculdade de Medicina da Universidade do Porto, Porto, Portugal
  6. 6Centro de Epidemiologia Hospitalar, Centro Hospitalar Universitário de São João, EPE, Porto, Portugal
  1. Correspondence to Dr Olga Laszczyńska, EPIUnit, Instituto de Saúde Pública da Universidade do Porto, Porto 4050-600, Portugal; olaszczynska{at}


Fluctuations in serum creatinine (SCr) during hospitalization may provide additional prognostic value beyond baseline renal function. This study aimed to identify groups of patients with distinct creatinine trajectories over hospital stay and assess them in terms of clinical characteristics and short-term mortality. This retrospective study included 35 853 unique adult admissions to a tertiary referral center between January 2012 and January 2016 with at least three SCr measurements within the first 9 days of stay. Individual SCr courses were determined using linear regression or linear-splines model and grouped into clusters. SCr trajectories were described as median SCr courses within clusters. Almost half of the patients presented with changing, mainly declining SCr concentration during hospitalization. In comparison to patients with an increase in SCr, those with a significant decline were younger, more often admitted via the emergency department, more often required a higher level of care, had fewer comorbidities and the more pronounced the fall in SCr, the greater the observed difference. Regardless of baseline renal function, an increase in SCr was related to the highest in-hospital mortality risk among compared clusters. Also, patients with normal renal function at admission followed by decreasing SCr were at higher risk of inpatient death, but lower 90-day postdischarge mortality than patients with a stable SCr. Acute changes in inpatient SCr convey important prognostic information and can only be interpreted by looking at their evolution over time. Recognizing underlying causes and providing adequate care is crucial for improving adverse prognosis.

  • creatinine
  • clinical research
  • acute kidney injury
  • kidney
  • clinical research
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  • Contributors OL: data cleaning and preparation, application of statistical data analysis techniques, manuscript preparation: creation and presentation of the work, including writing the initial draft. MS: design of methodology, interpretation of the results, overall manuscript preparation, including data presentation. JM: interpretation of the data and results; manuscript preparation: a critical review, commentary and revision. JP: interpretation of data and the results, manuscript preparation: a critical review, commentary and revision. AA: supervision, formulation of the research question, interpretation of the data and results, manuscript preparation: a critical review, commentary and revision.

  • Funding This study was supported by FEDER through the Operational Programme Competitiveness and Internationalization and national funding from the Foundation for Science and Technology (Portuguese Ministry of Science, Technology and Higher Education) under the Unidade de Investigação em Epidemiologia—Instituto de Saúde Pública da Universidade do Porto (EPIUnit) (POCI-01-0145-FEDER-006862; Ref. UID/DTP/04750/2013); the individual PhD Grant SFRH/BD/104037/2014 (electronic medical record-embedded predictive model for acute kidney injury in an acute care hospital') was co-founded by the FCT and POCH/FSE Programme.

  • Competing interests None declared.

  • Patient consent for publication Not required.

  • Ethics approval The study was approved by the Institutional Ethics Committee (Comissão de Ética para a Saúde do Centro Hospitalar Universitário de São João, reference number 365–15).

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Data availability statement No data are available.

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