No! Arthritis per se is not life threatening.

Rheumatic fever arthritis often leaves sequele in the heart which can be serious.
Chronic intake of drug, especially haphazardly taken can lead to serious damage in the body which can then threaten life.
Uncommonly, multiple systems including heart, can be affected in some rare forms of chronic arthritis (e.g. lupus).
However, chronic arthritis, can seriously affect the quality of life – both physical and mental.