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Multi-state models and arthroplasty histories after unilateral total hip arthroplasties: introducing the Summary Notation for Arthroplasty Histories.

Gillam MH, Ryan P, Salter A, Graves SE - Acta Orthop (2012)

Bottom Line: An increasing number of patients have several joint replacement procedures during their lifetime.At the end of the study period, 12% of the 84,759 patients had received a second hip, 3 times as many as had received a knee.We found differences in the progression of joint replacement procedures after the initial total hip arthroplasty regarding type of joint, age, and sex.

View Article: PubMed Central - PubMed

Affiliation: School of Population Health and Clinical Practice, University of Adelaide, Adelaide, Australia. marianne.gillam@adelaide.edu.au

ABSTRACT

Background and purpose: An increasing number of patients have several joint replacement procedures during their lifetime. We investigated the use and suitability of multi-state model techniques in providing a more comprehensive analysis and description of complex arthroplasty histories held in arthroplasty registries than are allowed for with traditional survival methods.

Patients and methods: We obtained data from the Australian Orthopaedic Association National Joint Replacement Registry on patients (n = 84,759) who had undergone a total hip arthroplasty for osteoarthritis in the period 2002-2008. We set up a multi-state model where patients were followed from their first recorded arthroplasty to several possible states: revision of first arthroplasty, either a hip or knee as second arthroplasty, revision of the second arthroplasty, and death. The Summary Notation for Arthroplasty Histories (SNAH) was developed in order to help to manage and analyze this type of data.

Results: At the end of the study period, 12% of the 84,759 patients had received a second hip, 3 times as many as had received a knee. The estimated probabilities of having received a second arthroplasty decreased with age. Males had a lower transition rate for receiving a second arthroplasty, but a higher mortality rate.

Interpretation: Multi-state models in combination with SNAH codes are well suited to the management and analysis of arthroplasty registry data on patients who experience multiple joint procedures over time. We found differences in the progression of joint replacement procedures after the initial total hip arthroplasty regarding type of joint, age, and sex.

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Multi-state model with 10 states for patients who received a first hip arthroplasty possibly followed by a second arthroplasty (hip or knee), revisions of these, and death.
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Figure 1: Multi-state model with 10 states for patients who received a first hip arthroplasty possibly followed by a second arthroplasty (hip or knee), revisions of these, and death.

Mentions: We developed a multi-state model for a restricted scenario in which patients were followed from their first recorded arthroplasty to several possible transient states: revision of the first arthroplasty, a second arthroplasty (hip or knee), revision of the second arthroplasty and the absorbing state, dead (we adopt the naming convention that ‘death’ is an event and ‘being dead’ is a state (Hougaard 1999)). The model, with 10 possible states that can be occupied (boxes) and paths that can be travelled (arrows), is illustrated in Figure 1. Based on this model , we calculated the numbers and proportions of patients in the cohort who experienced each event during the study period. For illustrative purposes, our model is simple; it only relates to 2 primary arthroplasties, first revisions of these, and death. The multi-state method can be extended to include further possible events, such as a third or fourth arthroplasty with associated revisions and re-revisions, but we do not do so here.


Multi-state models and arthroplasty histories after unilateral total hip arthroplasties: introducing the Summary Notation for Arthroplasty Histories.

Gillam MH, Ryan P, Salter A, Graves SE - Acta Orthop (2012)

Multi-state model with 10 states for patients who received a first hip arthroplasty possibly followed by a second arthroplasty (hip or knee), revisions of these, and death.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3369145&req=5

Figure 1: Multi-state model with 10 states for patients who received a first hip arthroplasty possibly followed by a second arthroplasty (hip or knee), revisions of these, and death.
Mentions: We developed a multi-state model for a restricted scenario in which patients were followed from their first recorded arthroplasty to several possible transient states: revision of the first arthroplasty, a second arthroplasty (hip or knee), revision of the second arthroplasty and the absorbing state, dead (we adopt the naming convention that ‘death’ is an event and ‘being dead’ is a state (Hougaard 1999)). The model, with 10 possible states that can be occupied (boxes) and paths that can be travelled (arrows), is illustrated in Figure 1. Based on this model , we calculated the numbers and proportions of patients in the cohort who experienced each event during the study period. For illustrative purposes, our model is simple; it only relates to 2 primary arthroplasties, first revisions of these, and death. The multi-state method can be extended to include further possible events, such as a third or fourth arthroplasty with associated revisions and re-revisions, but we do not do so here.

Bottom Line: An increasing number of patients have several joint replacement procedures during their lifetime.At the end of the study period, 12% of the 84,759 patients had received a second hip, 3 times as many as had received a knee.We found differences in the progression of joint replacement procedures after the initial total hip arthroplasty regarding type of joint, age, and sex.

View Article: PubMed Central - PubMed

Affiliation: School of Population Health and Clinical Practice, University of Adelaide, Adelaide, Australia. marianne.gillam@adelaide.edu.au

ABSTRACT

Background and purpose: An increasing number of patients have several joint replacement procedures during their lifetime. We investigated the use and suitability of multi-state model techniques in providing a more comprehensive analysis and description of complex arthroplasty histories held in arthroplasty registries than are allowed for with traditional survival methods.

Patients and methods: We obtained data from the Australian Orthopaedic Association National Joint Replacement Registry on patients (n = 84,759) who had undergone a total hip arthroplasty for osteoarthritis in the period 2002-2008. We set up a multi-state model where patients were followed from their first recorded arthroplasty to several possible states: revision of first arthroplasty, either a hip or knee as second arthroplasty, revision of the second arthroplasty, and death. The Summary Notation for Arthroplasty Histories (SNAH) was developed in order to help to manage and analyze this type of data.

Results: At the end of the study period, 12% of the 84,759 patients had received a second hip, 3 times as many as had received a knee. The estimated probabilities of having received a second arthroplasty decreased with age. Males had a lower transition rate for receiving a second arthroplasty, but a higher mortality rate.

Interpretation: Multi-state models in combination with SNAH codes are well suited to the management and analysis of arthroplasty registry data on patients who experience multiple joint procedures over time. We found differences in the progression of joint replacement procedures after the initial total hip arthroplasty regarding type of joint, age, and sex.

Show MeSH
Related in: MedlinePlus