how to replicate two-piecewise linear regression graph

[CathyVI]

Hi,

I am trying to replicate this graph. This is from a study https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7214907/

This is a  two-piecewise linear regression model. I will like to know the sas code which can be used to replicate this graph.

[WarrenKuhfeld]

Look at proc transreg.

[Ksharp]

Calling @Rick_SAS 

[Ksharp]

proc sgplot data=sashelp.heart(obs=1000);
loess x=weight y=height/clm nomarkers;
run;

[Rick_SAS]

See the article "Piecewise regression models and spline effects" for a discussion, example, and code.  The example uses PROC GLIMMIX, but also includes a reference to the PROC TRANSREG documentation, which contains a second example.

The example assumes that the two pieces of the model both have the same form (for example, linear or quadratic). If you want to mix-and-match models on separate domains, you can use PROC NLIN to construct a segmented regression model.