Purpose
To determine longitudinal rates of second retinal detachment operation and postoperative adverse outcomes after retinal detachment surgery in a nationally representative sample of older Americans.
Design
Retrospective, longitudinal cohort analysis.
Methods
A total of 9216 Medicare beneficiaries were identified from the Medicare 5% sample who were diagnosed with rhegmatogenous retinal detachment and underwent primary pars plana vitrectomy (PPV), scleral buckle, pneumatic retinopexy, or laser photocoagulation or cryotherapy alone. Rhegmatogenous retinal detachment, PPV, scleral buckle, pneumatic retinopexy, or laser photocoagulation/cryotherapy was ascertained from International Classification of Diseases and Current Procedural Terminology procedure codes. Rates of second retinal detachment operation and postoperative adverse outcomes were analyzed by cumulative incidence and logistic regression to control for prior adverse outcome measures and demographic factors.
Results
At 1-year follow-up, the rate of receipt of a second retinal detachment operation for beneficiaries who had undergone primary pneumatic retinopexy was much higher (40.6%, P < .0001) relative to the scleral buckle (19.2%) group. After controlling for demographic variables and ocular comorbidities, pneumatic retinopexy individuals were nearly 3 times more likely to receive a second retinal detachment surgery than scleral buckle individuals. No significant differences exist in risk of second retinal detachment surgery for the PPV compared to the scleral buckle group. Individuals receiving PPV were 2 times more likely to suffer adverse outcomes than were those undergoing scleral buckle. Results were robust in sensitivity analysis.
Conclusions
Rates of second operation were much higher after pneumatic retinopexy than PPV or scleral buckle, and rates of adverse outcomes were higher in PPV, even after controlling for risk factors and demographic variables.
The incidence of rhegmatogenous retinal detachment (RD), the most common type of retinal detachment, varies between 12.9 and 17.9 per 100 000 persons per year. The 5 primary interventions currently used to repair RRD are scleral buckle, pars plana vitrectomy (PPV), pneumatic retinopexy, combined PPV/scleral buckle, and laser and/or cryotherapy alone for simple, limited detachments. While scleral buckle is still considered to be the “gold standard” for repair of rhegmatogenous RD, PPV and pneumatic retinopexy have become increasingly popular in the last 2 or 3 decades, particularly with advances in wide-angle viewing systems, perfluorocarbon liquids, vitrectomy machines, endolaser, and intraocular gas tamponade. The purported advantages of primary PPV are improved internal search for retinal breaks, elimination of vitreous traction, and removal of the vitreous as a stimulant for proliferative vitreoretinopathy, while scleral buckling relieves circumferential traction at the vitreous base and avoids post-vitrectomy cataract progression and glaucoma. Unlike scleral buckling and PPV, which must be performed in the operating room, pneumatic retinopexy involves creation of retinopexy around retinal breaks with laser or cryotherapy followed by intraocular gas injection and can be performed in the clinic. Pneumatic retinopexy is considered to be most successful for primary retinal reattachment in phakic patients with limited superior retinal breaks who can cooperate with post-procedure head positioning.
As surgical practices evolve over time, it is helpful to have additional information about surgical outcomes and adverse events associated with each type of retinal detachment repair. The choice of initial surgical intervention is the most important predictor of primary anatomic success and final visual outcome. The vast majority of studies examining the success of retinal detachment repair have been single-center case series. There have been 4 prospective randomized controlled trials comparing primary PPV vs scleral buckle and 1 randomized trial examining pneumatic retinopexy vs scleral buckle. This study adds to existing evidence on success of different types of retinal detachment repair by examining data from a nationally representative longitudinal database spanning 17 years with 1 year of follow-up on each Medicare beneficiary. The 17-year span allowed us to examine cohort effects and test the efficacy of these procedures, comparing the most recent with earlier periods. This represents the largest reported sample of American patients undergoing retinal detachment repair, and offers the advantage of reducing surgeon- and center-specific factors.
Methods
Data
For this retrospective, longitudinal cohort analysis, Medicare 5% inpatient, outpatient, Part-B, and durable medical equipment claims files were used to identify a nationally representative sample of Medicare beneficiaries aged 67+ years undergoing retinal repair surgery and related adverse outcomes during 1991–2007. The 5% sample is created by selecting records with 05, 20, 45, 70, or 95 in positions 8 and 9 of the Health Insurance Claim number. In any given year, there are approximately 1.5 million individuals in the 5% sample. The data contained information on beneficiaries’ demographic characteristics and diagnostic (International Classification of Diseases, 9th Revision, Clinical Modification, ICD-9-CM) and procedural codes (Current Procedural Terminology, CPT-4; Healthcare Common Procedure Coding System, HCPCS) submitted with claims. Data were linked by a unique identifier, permitting construction of longitudinal, person-specific data from January 1, 1991 through December 31, 2007.
Sample Selection
We identified all individuals undergoing a PPV (CPT-4: 67108, 67036), scleral buckle (67107), pneumatic retinopexy (67110), and retinal repair surgery (laser photocoagulation, diathermy, or cryotherapy: laser/cryotherapy) (67101, 67105) between 1993 and 2007. Individuals who were coded under CPT code 67108 underwent a PPV “with or without” scleral buckle, and would have been categorized in our study as PPV.
We employed a 2-year look-back period to ensure that the individual had a previous diagnosis of rhegmatogenous retinal detachment (ICD-9-CM: 361.0×) to account for eye-related comorbidities, and to ensure that the surgery was the first retinal repair procedure an individual had undergone. We excluded all individuals receiving a first-study surgical procedure before age 67 or after age 95; individuals receiving a code for the following vitrectomy procedures on the same day as their first retinal detachment procedure: 67039, 67040, 67041, 67042, 67043 (as these codes are generally associated with treatment of diabetic retinopathy, macular holes, and epiretinal membranes); individuals diagnosed with proliferative diabetic retinopathy (PDR; ICD-9-CM: 362.02), tractional retinal detachment (361.81), chorioretinitis (363.0×, 363.1×, 363.2×), ruptured globe (871.0, 871.1, 871.2), presence of an intraocular foreign body (360.5×, 360.6×, 871.5, 871.6), or Stickler’s disease (756.0); and beneficiaries who entered a Medicare risk plan or who lived outside of the U.S. for 12+ months during the look-back period. We also excluded individuals undergoing a PPV and scleral buckle procedure (n=80) on the same day because we lacked statistical power to analyze this group.
Individuals were classified into 4 mutually exclusive categories based on their initial retinal detachment procedure: PPV, scleral buckle, pneumatic retinopexy, and laser/cryotherapy alone. Any individuals undergoing either laser/cryotherapy or pneumatic retinopexy who also had another retinal repair the same day were classified by the more complex procedure (eg, PPV or scleral buckle). Overall, our sample was slightly older (0.5 years older) and had a higher percentage of male and white subjects than the Medicare 5% sample from which our sample was drawn.
We followed individuals for 1 year after the initial retinal repair procedure or until censored. Individuals were censored if they died during follow-up, received another retinal repair procedure, or received any intraocular procedure, thus ensuring complications occurring after the receipt of a second procedure were not misattributed to the initial retinal repair procedure.
Adverse Events
Adverse events were identified using ICD-9-CM, CPT, and HCPCS codes. Complications were classified into 2 groups: 1) adverse outcomes (endophthalmitis [ICD-9-CM: 361.0], hypotony [360.30, 360.31, 360.32, 360.33], phthisis [360.40, 360.41, 360.42], moderate vision loss [369.6, 369.6×, 369.7, 369.7×, 369.8, 369.9], severe vision loss [369.4, 369.1, 369.1×, 369.2, 369.2×, 369.3], blindness/low vision aids [369.0, 369.0×; CPT-4: 92392; HCPCS: V2600, V2610, V2615]); and 2) additional surgical procedures (receipt of another PPV, scleral buckle, pneumatic retinopexy, laser/cryotherapy, or recurrent retinal repair [CPT-4: 67112]).
Severity
Using the look-back period, we created a continuous variable for severity of the rhegmatogenous retinal detachment, with least severe set to 1 (ICD-9-CM: 361.0, 361.00, 361.01; Table 1 ), moderately severe set to 2 (361.02, 361.03, 361.04), and most severe receiving a 3 (361.05, 361.06, 361.07) ( Table 1 ). Individuals receiving more than 1 rhegmatogenous retinal detachment diagnosis in multiple severity categories were coded with the most severe diagnosis they received during the look-back period.
| ICD-9-CM Code | Definition |
|---|---|
| 1 (least severe) | |
| 361.0 | Retinal detachment with retinal defect |
| 361.00 | Retinal detachment with retinal defect, unspecified |
| 361.01 | Recent detachment, partial, with single defect |
| 2 (moderate severity) | |
| 361.02 | Recent detachment, partial, with multiple defects |
| 361.03 | Recent detachment, partial, with giant tear |
| 361.04 | Recent detachment, partial, with retinal dialysis |
| Dialysis (juvenile) of retina (with detachment) | |
| 3 (most severe) | |
| 361.05 | Recent detachment, total or subtotal |
| 361.06 | Old detachment, partial Delimited old retinal detachment |
| 361.07 | Old detachment, total or subtotal |
Additional Covariates
To account for other eye comorbidities present at the time of surgery, we included covariates for prior diagnosis of cataract (ICD-9-CM: 366.0), myopia (360.21, 367.1), lattice degeneration (362.63), proliferative vitreoretinopathy (PVR: 362.2×), visual impairment (see Adverse Events), and a severe complication (see Adverse Events); receipt of a prior intraocular procedure; and receipt of a cataract extraction surgery (CPT-4: 66830-66984, ICD-9-CM: V45.61, including a diagnosis of pseudophakia [V43.1] or aphakia [379.31]).
Cohort Variables
We created 3 separate variables identifying the time period in which the procedures were performed to examine whether or not complication rates or additional operation rates changed over time. Individuals undergoing a retinal repair procedure from 1993 to 1997 were Cohort 1. Cohort 2 was composed of those receiving a procedure from 1998 to 2002, and Cohort 3 was defined as those receiving a procedure from 2003 to 2006. Sample sizes by cohort were 3554, 3192, and 2550 for Cohorts 1, 2, and 3, respectively.
Analysis
Using the 5 mutually exclusive categories described above, we performed Student t tests to examine whether or not statistically significant differences existed at baseline, using scleral buckle as the comparison group, and subsequently considering second retinal detachment operation/adverse outcome rates among the procedure groups. We then used logit analysis to determine whether or not second operation and adverse outcome rates differed by procedure type, adjusting for baseline characteristics and comorbid eye conditions.
We performed a sensitivity analysis, assigning individuals with only 1 diagnosis of an adverse event a 1, individuals with 2+ diagnoses of adverse events a 2, and all others a 0. We performed ordered logit analysis to determine whether or not requiring 2 diagnoses of an adverse outcome affected our results. Because of the small number of 2+ diagnoses of adverse events (n = 77), we did not perform a simple logit analysis.
Results
In the 5% random sample of medicare beneficiaries from 1991 to 2007, 9216 beneficiaries were identified with a diagnosis of rhegmatogenous retinal detachment who also satisfied the study’s eligibility criteria. Compared to the scleral buckle group (1.972), the severity of retinal detachment was significantly lower for the pneumatic retinopexy (1.785, P < .0001) and the laser/cryotherapy groups (1.597, P < .0001) and slightly higher for the PPV group (2.016, P = .048; Table 2 ). Individuals undergoing PPV were more likely to have received a prior diagnosis of PVR (2.3% vs 0.6%; P < .0001) than scleral buckle patients. In terms of lens status, patients undergoing laser/cryotherapy were more likely to have cataract (44.9%, P = .021) than patients undergoing scleral buckle (41.2%). The PPV group (53.5%, P < .0001) was more likely to have undergone cataract surgery in the previous 2 years, while the pneumatic retinopexy group (39.7%, P = .001) was less likely to have undergone cataract surgery in the previous 2 years than the scleral buckle group (45.2%). Individuals undergoing pneumatic retinopexy had the lowest rate of lattice degeneration of any group (1.1%, P = 0.04). Those undergoing PPV were significantly more likely to have received prior intraocular procedures (14.7% vs 6.2%; P < .0001), and to have had severe complications (3.2% vs 0.6%; P < .0001), than were patients undergoing scleral buckle. Medicare beneficiaries undergoing the 5 different primary procedures were not significantly different in terms of gender. Individuals undergoing pars plana vitrectomy and scleral buckle were slightly older on average than were those undergoing pneumatic retinopexy and laser/cryotherapy. Those undergoing PPV had a greater likelihood of receiving Medicaid coverage compared to those undergoing scleral buckle (7.7% vs 5.2%; P < .0001).
| Scleral Buckle | Pars Plana Vitrectomy | Pneumatic Retinopexy | Laser or Cryotherapy | Full Sample | ||||
|---|---|---|---|---|---|---|---|---|
| Mean | Mean | P Value | Mean | P Value | Mean | P Value | Mean | |
| Severity (rates unless otherwise noted) | ||||||||
| Severity of RD (1-3) | 1.972 | 2.016 | .048 | 1.785 | <.0001 | 1.597 | <.0001 | 1.907 |
| Proliferative vitreoretinopathy | 0.006 | 0.023 | <.0001 | 0.002 | .017 | 0.005 | 0.012 | |
| RD risk factors (rates) | ||||||||
| Cataract | 0.412 | 0.392 | 0.405 | 0.449 | .021 | 0.409 | ||
| Cataract surgery | 0.452 | 0.535 | <.0001 | 0.397 | .001 | 0.288 | 0.451 | |
| Myopia | 0.026 | 0.033 | 0.026 | 0.027 | 0.029 | |||
| Lattice degeneration | 0.019 | 0.028 | .023 | 0.011 | .040 | 0.037 | .002 | 0.024 |
| Prior intraocular procedure | 0.062 | 0.147 | <.0001 | 0.088 | .006 | 0.048 | 0.094 | |
| Prior severe complication | 0.006 | 0.032 | <.0001 | 0.003 | 0.003 | 0.015 | ||
| Prior visual impairment | 0.047 | 0.057 | 0.041 | 0.033 | .018 | 0.048 | ||
| Demographic characteristics (rates unless otherwise noted) | ||||||||
| Male | 0.516 | 0.511 | 0.546 | 0.522 | 0.519 | |||
| Black | 0.018 | 0.041 | <.0001 | 0.011 | 0.043 | <.0001 | 0.030 | |
| Other race | 0.015 | 0.025 | .003 | 0.021 | 0.040 | <.0001 | 0.023 | |
| Age (years) | 75.062 | 76.036 | <.0001 | 74.438 | .002 | 74.023 | <.0001 | 75.185 |
| Medicaid | 0.052 | 0.077 | <.0001 | 0.050 | 0.055 | 0.061 | ||
| Observations | 3248 | 3406 | 1151 | 1411 | 9216 | |||
Complication rates were divided into additional retinal detachment operation and adverse outcomes. The latter was subdivided into severe complications (endophthalmitis, hypotony, and phthisis) and visual impairment (moderate vision loss, severe vision loss, and blindness). Compared to scleral buckle (19.2%), rates of second retinal detachment operation were highest for pneumatic retinopexy (40.6%; P < .001), slightly higher for PPV (21.2%; P = .044), and lower for laser/cryotherapy (17.2%; P = .043). If a second operation was performed, it was most likely to be PPV for all therapeutic categories except laser/cryotherapy. Rates of adverse outcomes overall (3.5%; P = .0001) and severe complications (1.2%; P = .0001) were highest for PPV ( Table 3 ). The only cases of hypotony occurred in the PPV group. Rates of visual impairment were also highest for the PPV group (2.6%; P = .002), whether it was moderate or severe vision loss or blindness ( Table 3 ).
| Scleral Buckle | Pars Plana Vitrectomy | Pneumatic Retinopexy | Laser or Cryotherapy | Full Sample | ||||
|---|---|---|---|---|---|---|---|---|
| Complication | Mean | Mean | P Value | Mean | P Value | Mean | P Value | Mean |
| PANEL A. MAIN ANALYSIS | ||||||||
| Second operation | 0.192 | 0.212 | .044 | 0.406 | <.0001 | 0.172 | .043 | 0.223 |
| Pars plana vitrectomy | 0.128 | 0.174 | <.0001 | 0.241 | <.0001 | 0.068 | <.0001 | 0.150 |
| Scleral buckle | 0.034 | 0.009 | <.0001 | 0.105 | <.0001 | 0.043 | 0.035 | |
| Pneumatic retinopexy | 0.016 | 0.014 | 0.058 | <.0001 | 0.010 | 0.020 | ||
| Laser or cryotherapy | 0.030 | 0.024 | 0.109 | <.0001 | 0.094 | <.0001 | 0.048 | |
| Recurrent repair retinal detachment | 0.022 | 0.022 | 0.014 | 0.004 | <.0001 | 0.018 | ||
| Adverse outcomes | 0.017 | 0.035 | .0001 | 0.006 | .002 | 0.012 | 0.021 | |
| Severe complication | 0.004 | 0.012 | .0001 | 0.003 | 0.004 | 0.007 | ||
| Endophthalmitis | 0.002 | 0.003 | 0.003 | 0.003 | 0.003 | |||
| Hypotony | 0.000 | 0.002 | .006 | 0.000 | 0.000 | 0.001 | ||
| Phthisis | 0.001 | 0.009 | <.0001 | 0.000 | .046 | 0.001 | 0.004 | |
| Visual impairment | 0.013 | 0.026 | .002 | 0.005 | .010 | 0.008 | 0.016 | |
| Moderate vision loss | 0.009 | 0.014 | .043 | 0.005 | 0.007 | 0.010 | ||
| Severe vision loss | 0.003 | 0.009 | .0008 | 0.000 | .003 | 0.001 | 0.004 | |
| Blindness or low vision aid | 0.002 | 0.006 | .022 | 0.000 | .005 | 0.001 | 0.003 | |
| Observations | 3248 | 3406 | 1151 | 1411 | 9216 | |||
| PANEL B. SENSITIVITY ANALYSIS | ||||||||
| Adverse outcomes | 0.007 | 0.014 | .016 | 0.004 | 0.005 | 0.009 | ||
| Severe complication | 0.002 | 0.006 | .018 | 0.002 | 0.003 | 0.004 | ||
| Endophthalmitis | 0.002 | 0.002 | 0.002 | 0.003 | 0.002 | |||
| Hypotony | 0.000 | 0.001 | 0.000 | 0.000 | 0.0002 | |||
| Phthisis | 0.000 | 0.005 | .000 | 0.000 | 0.000 | 0.002 | ||
| Visual impairment | 0.005 | 0.008 | 0.002 | 0.002 | 0.005 | |||
| Moderate vision loss | 0.003 | 0.005 | 0.002 | 0.002 | 0.003 | |||
| Severe vision loss | 0.001 | 0.003 | .025 | 0.000 | 0.000 | 0.001 | ||
| Blindness or low vision aid | 0.002 | 0.002 | 0.000 | .025 | 0.000 | .025 | 0.001 | |
| Observations | 3248 | 3406 | 1151 | 1411 | 9216 | |||
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