Purpose To evaluate indications and factors that influence long-term clinical outcomes and revision rates for reverse shoulder arthroplasty (RSA) in shoulders with irreparable massive rotator cuff tears (mRCTs) or cuff tear arthropathies (CTAs). Methods The authors retrospectively evaluated a consecutive series of shoulders with no fracture sequelae that underwent primary RSA between 2011 and 2013. Independent observers collected demographic data, surgical techniques, and implant types, as well as primary outcome measures such as American Shoulder and Elbow Society (ASES) score and Constant score (CS). Study design Case series, level IV. Results From the initial series of 123 patients that underwent RSA, 29 patients died (24%) for reasons unrelated to the shoulder arthroplasty, 11 were lost to follow-up (9%), and 4 required revision surgery (3%). The final cohort of 79 patients comprised 55 women (70%), and 24 men (30%), aged 72.7 ± 7.0. At a final follow-up of 8.9 ± 0.6 years (range: 7.4-10.3) the absolute CS was 59.0 ± 16.2, the age-/sex-adjusted CS was 76.6 ± 41.2, and ASES was 77.1 ± 20.3. Univariable analysis revealed no associations for absolute CS, but revealed that age-/sex-adjusted CS was significantly lower for patients with high blood pressure (β = −15.8, p = .025). Conclusions At a minimum follow-up of 7.4 years, the absolute CS was 59.0 ± 16.2, the age-/sex-adjusted CS was 87.4 ± 24.1 and ASES was 77.1 ± 20.3. When stratifying the outcomes of RSA by indication, there were no significant differences in patients with mRCTs versus CTA in terms of absolute CS, age-/sex-adjusted CS, and ASES. Univariable analysis revealed no association with absolute and age-/sex-adjusted CS for type of indication or surgical approach.