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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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Related in: MedlinePlus

State occupation probabilities for patients in 3 age groups after first hip arthroplasty, based on the model in Figure 1 (revision: state 2; hip: state 3; knee: state 4; dead: state 10; other: states 5–9).
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Figure 3: State occupation probabilities for patients in 3 age groups after first hip arthroplasty, based on the model in Figure 1 (revision: state 2; hip: state 3; knee: state 4; dead: state 10; other: states 5–9).

Mentions: The estimated state occupation probabilities at different time points since the first recorded hip arthroplasty for each age group are presented in Figure 3. Because so few patients experienced events beyond the second event after the initial arthroplasty (Table 1, states 5–9), these events were combined. Among patients in the 2 youngest age groups, it appears that at each time point after having received the first hip arthroplasty the probability of occupying state 3 (having received a second hip arthroplasty and no further events) was higher than occupying any of the other event states. For the oldest age group, the probability of occupying state 3 was the highest until approximately 3 years after the first hip prosthesis; thereafter, the probability of being in the state ‘dead’ was the highest. The probability of occupying state 3 decreased with increasing age. For example, 5 years after having received a first total hip arthroplasty approximately 20% of patients aged 65–74 years were estimated to have received a contralateral hip (and had not experienced any other event in this model) as compared to 10% of patients in the oldest age group (aged 75–84 years). The estimated probability of occupying state 4 (having received a knee arthroplasty) rather than occupying state 3 was much lower throughout the study period. Thus, when a patient received a hip first, this was more likely to be followed by another hip than a knee.


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)

State occupation probabilities for patients in 3 age groups after first hip arthroplasty, based on the model in Figure 1 (revision: state 2; hip: state 3; knee: state 4; dead: state 10; other: states 5–9).
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 3: State occupation probabilities for patients in 3 age groups after first hip arthroplasty, based on the model in Figure 1 (revision: state 2; hip: state 3; knee: state 4; dead: state 10; other: states 5–9).
Mentions: The estimated state occupation probabilities at different time points since the first recorded hip arthroplasty for each age group are presented in Figure 3. Because so few patients experienced events beyond the second event after the initial arthroplasty (Table 1, states 5–9), these events were combined. Among patients in the 2 youngest age groups, it appears that at each time point after having received the first hip arthroplasty the probability of occupying state 3 (having received a second hip arthroplasty and no further events) was higher than occupying any of the other event states. For the oldest age group, the probability of occupying state 3 was the highest until approximately 3 years after the first hip prosthesis; thereafter, the probability of being in the state ‘dead’ was the highest. The probability of occupying state 3 decreased with increasing age. For example, 5 years after having received a first total hip arthroplasty approximately 20% of patients aged 65–74 years were estimated to have received a contralateral hip (and had not experienced any other event in this model) as compared to 10% of patients in the oldest age group (aged 75–84 years). The estimated probability of occupying state 4 (having received a knee arthroplasty) rather than occupying state 3 was much lower throughout the study period. Thus, when a patient received a hip first, this was more likely to be followed by another hip than a knee.

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